Have I wasted my time

[Riotvan88]

Hi all seeking some advice

I have built a smit Rotterdam kit. Intention was always to make it RC. Here is current progress

However I am now deeply concerned I have made a huge error.  When looking for advise on glassing the hull I was advised I could use epoxy resin only (no cloth) with additives 422 Barrier Coat...see thread below

This was recommended by a couple of people so I went down this route and ended up painting the hull with Smiths penetrating epoxy sealer then did two coats of west systems Gflex epoxy with 422 barrier coat additive added. I'm now worried this was wrong and now the boat is unsuitable to be RC. This epoxy is what they on full size yachts and dinghys. (Used it myself to fill damage on an Enterprise dinghy)

 

Any thoughts? perhaps I'm worried over nothing? would appreciate any wisdom on this. Future builds I'll definitely use glass. I just hope I haven't limited this to a static build.  

Edited November 10, 2022 by Riotvan88

[JerryTodd]

Most glass models don't LIVE in the water.  They don't sit at docks for months on end, so while you may have issues with water intrusion (leaks), you're not looking at osmosis caused blistering and the like as seen on neglected yachts, especially with epoxy.  My hulls are wood, covered with glass cloth in Polyester resin, and coated with poly resin inside, they're all over a decade old now and doing fine.

My danger is any sort of through-hull like the rudder-post where water can get in to the wood.  Any hole under the waterline is made larger, filled with epoxy, then made to size so all the hole exposes is epoxy.  On an all-glass hull, that's not an issue, though is is best to coat the inside of any through-hull hole so water can seep into any cloth that didn't get fully saturated during construction - or you can get a blister and de-lamination.

 

All that they were describing sounds like what I've been doing with my friend on his Mariner 32 ketch, grinding blisters; check the hull with meters till it's dry enough to putty the craters; apply three barrier coats, then bottom paint just before we launch.  It's back-breaking work for someone in their 60's

 

Was it a waste of time?  Well, yeah, and worst, a waste of money, that stuff ain't cheap.  But, what's done is done, and it won't hurt the model.  Hopefully you'll build more models and will know you don't need to go through all that again.

My hulls build logs are linked below...

Edited November 10, 2022 by JerryTodd

[Riotvan88]

17 minutes ago, JerryTodd said:

Most glass models don't LIVE in the water.  They don't sit at docks for months on end, so while you may have issues with water intrusion (leaks), you're not looking at osmosis caused blistering and the like as seen on neglected yachts, especially with epoxy.  My hulls are wood, covered with glass cloth in Polyester resin, and coated with poly resin inside, they're all over a decade old now and doing fine.

My danger is any sort of through-hull like the rudder-post where water can get in to the wood.  Any hole under the waterline is made larger, filled with epoxy, then made to size so all the hole exposes is epoxy.  On an all-glass hull, that's not an issue, though is is best to coat the inside of any through-hull hole so water can seep into any cloth that didn't get fully saturated during construction - or you can get a blister and de-lamination.

 

All that they were describing sounds like what I've been doing with my friend on his Mariner 32 ketch, grinding blisters; check the hull with meters till it's dry enough to putty the craters; apply three barrier coats, then bottom paint just before we launch.  It's back-breaking work for someone in their 60's

 

Was it a waste of time?  Well, yeah, and worst, a waste of money, that stuff ain't cheap.  But, what's done is done, and it won't hurt the model.  Hopefully you'll build more models and will know you don't need to go through all that again.

My hulls build logs are linked below...

Hi thanks for the reply. I think you may have not understood the problem. I did not use any glass at all. I treated the wood with a penetrating epoxy then 2 coats of marine epoxy only no glass.

 

I did this based on some recommendations (seems others have done it also)

 

My worry now is that without glass the model is only suitable for display. Interested to see what others think. 

[Roger Pellett]

Put it in the bathtub and see what happens!  😊

[kurtvd19]

I would add epoxy to the interior of the hull from the waterline (at minimum) to the keel paying extra attention to any hull penetrations.  If unable to access the entire area I described I would absolutely get epoxy around the prop shaft penetration and any other penetrations at minimum.  The hull will not be in the water for days at a time, more likely less that a couple of hours.  It takes time for water to soak into any exposed wood you might have missed and if you are like most RC boaters it will have at least a week to dry out - keep the interior of the hull accessible to the air.

Next time use glass cloth.  It is easier than you think.

Kurt

 

[Riotvan88]

2 minutes ago, kurtvd19 said:

I would add epoxy to the interior of the hull from the waterline (at minimum) to the keel paying extra attention to any hull penetrations.  If unable to access the entire area I described I would absolutely get epoxy around the prop shaft penetration and any other penetrations at minimum.  The hull will not be in the water for days at a time, more likely less that a couple of hours.  It takes time for water to soak into any exposed wood you might have missed and if you are like most RC boaters it will have at least a week to dry out - keep the interior of the hull accessible to the air.

Next time use glass cloth.  It is easier than you think.

Kurt

 

Thanks for the reply. I coated the whole hull in epoxy atond payed special attention to all hull penetrations. Then several coats of automotive primer and costs of paint. Inside has been varnished but could add epoxy to it as well. Boat will be on water 6-12 times a year summer only.

[kurtvd19]

You should be fine to go.

[Riotvan88]

33 minutes ago, kurtvd19 said:

You should be fine to go.

I have built two small test hulls each the size of a matchbox one with the paint system only and one with the epoxy coating only. Will build a third with epoxy + paint to be truly representative of my hull.

 

I'm going to float these in a bowl to see how long the coatings last. 

[Bob Cleek]

I don't expect you should have any problem if you coated with G-Flex. The absence of a glass cloth matrix can result in cracking of a rigid polyester resin coating when (and if) the wood expands. However, G-Flex is just that, flexible. This feature is intended to compensate for the expansion of the wood structure. Your use of CPES as a primer should provide an excellent base for the G-Flex. Do make sure your wood below the waterline is well coated. If so, I'd say "splash her when the paint's dry!"

 

[Riotvan88]

9 hours ago, Bob Cleek said:

I don't expect you should have any problem if you coated with G-Flex. The absence of a glass cloth matrix can result in cracking of a rigid polyester resin coating when (and if) the wood expands. However, G-Flex is just that, flexible. This feature is intended to compensate for the expansion of the wood structure. Your use of CPES as a primer should provide an excellent base for the G-Flex. Do make sure your wood below the waterline is well coated. If so, I'd say "splash her when the paint's dry!"

 

Cheers Bob I did two coats with Gflx one with water barrier additive and a final with fairing additive. The whole model was done in CPES as well as Gflex including decks and superstructure albiet only one coat of Gflex for those areas. Outdoor varnish was applied to all inside surfaces

 

My concern is during all the priming, sanding, painting (done over months) I may have sanded through in some spots without realizing. Probably not but impossible to know now.

 

I plan to give several coats of satin lacquer at the end which should also provide an additional waterproof barrier as well.

 

I've made some small test hulls one with paint and topcoat only to simulate a potential sand through area and one with CPES, Gflex and paint to simulate the the hull generally. I'm going to place these in water 24/7 to see how long these coatings last.

Edited November 11, 2022 by Riotvan88

[Bob Cleek]

9 hours ago, Riotvan88 said:

My concern is during all the priming, sanding, painting (done over months) I may have sanded through in some spots without realizing. Probably not but impossible to know now.

This is true and it's a very common mistake made by inexperienced finishers. This particularly problematic when one is working with a clear coating that is particularly susceptible to ultraviolet damage, such as varnish or epoxy resin. Frequently, the newbie will apply a coat of varnish, even varnish with UV inhibitors) and then, obeying the instructions to "sand between coats," sand off the coat they've last applied. When all is said and done, they think they have applied the required "eight coats of varnish" and can't figure out why their varnish job, which looked great when they were finished, started going to pot in a couple of months. Instead of eight coats of UV inhibitors, they had the equivalent of one coat! This isn't of much import when painting models, though. They don't have to withstand the continual exposure to direct sunlight. (We hope!)

 

However, the CPES should have soaked into the wood sufficiently deep to provide a decent sealing, later sanding notwithstanding. As others have noted, your subsequent coats of barrier coat and various other things should be more than adequate to prevent water damage for the use intended. Remember, though, that epoxy is not "waterproof."  It's moisture permeable to some extent, depending upon the length of exposure, of course. There's a big difference between "moisture" and "water," though. As long as you have any sort of paint on it, there's little chance of the hull getting waterlogged.  

 

"Several coats of satin lacquer" will just add that much more protection to the wood, but it's probably not necessary. It's a matter of personal preference, I suppose, but I'm not much of a fan of "satin lacquer," or "satin" anything, for that matter, except in situations where a protective coating is required on finely detailed surfaces that can't be rubbed. "Canned satin" finishes are simply paint with "dirt" added to dull the finish. On a nice smooth hull, I opt for applying the finish coats without "satin" added, and, if they need flattening down, I hand-rub them with rottenstone and pumice the old-school way, yielding a much finer finish than "paint-on satin."

[JerryTodd]

Like I said, my hulls are wood.  I glass the outside to act as a wrap because the wood in in planks with a lot of seams and joints.  Coating it will "waterproof" it but it's still wood and it will move, and seams can still open - the cloth helps with that.

 

In the image the glassed hull sat for a long time in the garage with the temperature changes that entails, and a seam opened slightly, cracking the filler putty.  The 4oz glass cloth helped retain the hull's integrity.

 

 

[Riotvan88]

6 hours ago, JerryTodd said:

Like I said, my hulls are wood.  I glass the outside to act as a wrap because the wood in in planks with a lot of seams and joints.  Coating it will "waterproof" it but it's still wood and it will move, and seams can still open - the cloth helps with that.

 

In the image the glassed hull sat for a long time in the garage with the temperature changes that entails, and a seam opened slightly, cracking the filler putty.  The 4oz glass cloth helped retain the hull's integrity.

 

 

I see the problem with future expansion/contraction etc and I do wish I'd used glass now just for piece of mind. I'm semi tempted to strip paint and glass it but at same time I really really don't want to.

 

That said the Gflex is used to seal full sized dinghys and day sailor boats. It has a much higher elasticity than polyester according to their website it's designed to create structural bonds in wooden constructions and does mention it's ability to accept flex and expansion. 

 

Didn't many older models simply use sanding sealer or varnish and do fine? 

Edited November 12, 2022 by Riotvan88

[Riotvan88]

17 hours ago, Bob Cleek said:

This is true and it's a very common mistake made by inexperienced finishers. This particularly problematic when one is working with a clear coating that is particularly susceptible to ultraviolet damage, such as varnish or epoxy resin. Frequently, the newbie will apply a coat of varnish, even varnish with UV inhibitors) and then, obeying the instructions to "sand between coats," sand off the coat they've last applied. When all is said and done, they think they have applied the required "eight coats of varnish" and can't figure out why their varnish job, which looked great when they were finished, started going to pot in a couple of months. Instead of eight coats of UV inhibitors, they had the equivalent of one coat! This isn't of much import when painting models, though. They don't have to withstand the continual exposure to direct sunlight. (We hope!)

 

However, the CPES should have soaked into the wood sufficiently deep to provide a decent sealing, later sanding notwithstanding. As others have noted, your subsequent coats of barrier coat and various other things should be more than adequate to prevent water damage for the use intended. Remember, though, that epoxy is not "waterproof."  It's moisture permeable to some extent, depending upon the length of exposure, of course. There's a big difference between "moisture" and "water," though. As long as you have any sort of paint on it, there's little chance of the hull getting waterlogged.  

 

"Several coats of satin lacquer" will just add that much more protection to the wood, but it's probably not necessary. It's a matter of personal preference, I suppose, but I'm not much of a fan of "satin lacquer," or "satin" anything, for that matter, except in situations where a protective coating is required on finely detailed surfaces that can't be rubbed. "Canned satin" finishes are simply paint with "dirt" added to dull the finish. On a nice smooth hull, I opt for applying the finish coats without "satin" added, and, if they need flattening down, I hand-rub them with rottenstone and pumice the old-school way, yielding a much finer finish than "paint-on satin."

I know what you mean especially with varnish. I definatley didn't sand the epoxy off generally but it's possible certain spots might have been sanded though I can't really remember.

 

I did lots of primer layers sanding between coats and occasionally sanded back to the epoxy layer in spots. I do remember mixing up small batches of epoxy to patch areas I suspected a sand though might have ocured but always a chance I missed one or two. 

 

That's the problem with an on/off project. Can't remember half of what I did to build it.

[kurtvd19]

For the future I suggest you do a personal build log.  I have always done this so I can remember the paints and glues used and where used.  If I mix a color I record the paints used and the ratio of each so in case of needing a repair I can duplicate the color.  Woods and other materials and where they were used is also a good idea to record.  Upon completion of a model all the information is saved in a note book for later use.

 

Of course if you are doing a build log to share here you can everything recorded here.

 

 

[Riotvan88]

1 hour ago, kurtvd19 said:

For the future I suggest you do a personal build log.  I have always done this so I can remember the paints and glues used and where used.  If I mix a color I record the paints used and the ratio of each so in case of needing a repair I can duplicate the color.  Woods and other materials and where they were used is also a good idea to record.  Upon completion of a model all the information is saved in a note book for later use.

 

Of course if you are doing a build log to share here you can everything recorded here.

 

 

That's a great idea, I have taken pictures along the way but I've not really recorded anything down. A bill of materials would be a good idea next time.

[Riotvan88]

On 11/11/2022 at 7:30 PM, Bob Cleek said:

This is true and it's a very common mistake made by inexperienced finishers. This particularly problematic when one is working with a clear coating that is particularly susceptible to ultraviolet damage, such as varnish or epoxy resin. Frequently, the newbie will apply a coat of varnish, even varnish with UV inhibitors) and then, obeying the instructions to "sand between coats," sand off the coat they've last applied. When all is said and done, they think they have applied the required "eight coats of varnish" and can't figure out why their varnish job, which looked great when they were finished, started going to pot in a couple of months. Instead of eight coats of UV inhibitors, they had the equivalent of one coat! This isn't of much import when painting models, though. They don't have to withstand the continual exposure to direct sunlight. (We hope!)

 

However, the CPES should have soaked into the wood sufficiently deep to provide a decent sealing, later sanding notwithstanding. As others have noted, your subsequent coats of barrier coat and various other things should be more than adequate to prevent water damage for the use intended. Remember, though, that epoxy is not "waterproof."  It's moisture permeable to some extent, depending upon the length of exposure, of course. There's a big difference between "moisture" and "water," though. As long as you have any sort of paint on it, there's little chance of the hull getting waterlogged.  

 

"Several coats of satin lacquer" will just add that much more protection to the wood, but it's probably not necessary. It's a matter of personal preference, I suppose, but I'm not much of a fan of "satin lacquer," or "satin" anything, for that matter, except in situations where a protective coating is required on finely detailed surfaces that can't be rubbed. "Canned satin" finishes are simply paint with "dirt" added to dull the finish. On a nice smooth hull, I opt for applying the finish coats without "satin" added, and, if they need flattening down, I hand-rub them with rottenstone and pumice the old-school way, yielding a much finer finish than "paint-on satin."

After some rumaging around I've found the empty tins of everything I've used. The complete schedule is 

 

Several coats of CPES 

1X coat WS Gflex with water barrier additive

1X coat WS Gflex with fairing additive

2X full cans automotive high build primer

2X full cans plasticoat outdoor trade paint Black above waterline 

2X full cans plasticoat red oxide below water line 

 

The boat looked smooth but each time I put paint on I'd spot flaws which is why I've used so many cans. Paint, sand paint, sand. 

 

Anyway I plan to add plimsol markins with decals and so will add a top coat to seal them in. Thus the top coat need be water proof to protect the decals. 

 

Hopfully the end result will be a matrix of layers that will keep her dry.

[Bob Cleek]

Sometimes it takes a lot to get a perfect finish.  

[Riotvan88]

4 hours ago, Bob Cleek said:

Sometimes it takes a lot to get a perfect finish.  

Not perfect but not willing to spend any more on paint 

[Bob Cleek]

I sure can't see any flaws in that paint job. It looks great! Nice work!

 

If you have some very minor flaws, such as a dust speck or three, you can always rub them out with rottenstone and pumice. These are very fine abrasive powders that you apply to a soft, damp cloth and rub on the surface. The longer you rub the better the finish. They should be available in powder form at any paint store. Auto parts and paint stores carry it premixed in a creamy liquid form, as well. These hand rubbing abrasives permit you to "fine tune" your finish from a flat matte to a high gloss, depending upon how much elbow grease you want to apply. 

 

The whole point of hand-rubbing is that it permits you to address a small area of a larger paint job and repair a flaw without having to repaint the entire piece.

 

Hand rubbing is a technique that has a bit of a learning curve, but it's more about practice than information. Try it on a test piece before going at a finished workpiece. Once you get the hang of how to vary the level of gloss, you'll be able to easily match spots you want to deal with. Here's a video that covers the subject of getting a perfect hand-rubbed finish in a lot of detail, but is well worth taking the time to watch. 

 

Edited November 15, 2022 by Bob Cleek