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Hello

 

I've decided to build my 1st scratch build. I've got some plans for zwarte see tug. My idea is to use the plans to get the frames laser cut using 5mm ply. Does anyone have any suggestions on companies that do this service? any suggestions or advice?

Cheers

 

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53 minutes ago, Riotvan88 said:

any suggestions or advice?

I am guessing that you will be doing this POB?

If so, then what you are naming "the frames"  are named "bulkheads" in the POB world.  What they actually are = moulds or molds.   

 

Laser cutting makes sense if you are setting up to make 100 identical kits and want a convenient and economical way to get multiple identical parts.  Unless you are doing the laser programing for computer reasons instead of just tool to get model parts,  the time spent is difficult to justify to make one copy.

 

If you do not have a motorized scroll saw, for one model and a hull that is not likely to have a lot of moulds, a hand operated fret saw or coping saw will do an excellent job of freeing the moulds from a sheet of wood or plywood.  Sanding blocks will get you to the line.  You can also use thicker stock than a laser will want to vaporize.

 

Get the patterns by tracing what is on the plans if 1:1 or use a scanner -  If the scale is to be different, there are Xerox machines that reduce or enlarge -  or scan the plans of the moulds into your computer and use a drawing program to change to scale and print the patterns out.  PS in the cloud has a <one month free trial if you do not own the necessary program.

 

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Posted (edited)
6 hours ago, Riotvan88 said:

 

I've decided to build my 1st scratch build

Rio 

Congrats!!  Am I correct in assuming you do not have a scroll saw or coping saw to cut them out yourself?   I am pretty sure there are a number of folks here that will be interested in knowing how you do with laser cutting, including number of bulkheads you will be getting and total cost.  Will you be using your paper plans or will you redraw them first?  

Thanks in advance.

Allan

Edited by allanyed
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7 hours ago, Riotvan88 said:

I've decided to build my 1st scratch build. I've got some plans for zwarte see tug.

 

I did the frames for my 85 ft Harbor tug on a scroll saw.

 

You can pick them up pretty cheaply locally, our club here in the UK has one looking for a home right now. Shipping would probably cost too much.

Tim

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I would have said for a one off project just printing them out and sticking them onto the plywood and then cut by scroll saw would be easy enough. But the costs of hobbyist 2d plotters with laser say in the 20 to 30w range would be enough to cut 5mm plywood.. I saw someone on this forum who has 40w laser and that cut one sided... almost too strong it burnt it quite a lot .. or you flip it and get less powerful laser.

 

The motor controls on the 2d plotter and width of laser dot would be considations.

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That's something I never thought about. I spent several decades in scale R/C aircraft hobby scratch building. There are a number of laser cutting companies that cut airplane part and entire kits from plans. I know of a few that advertise if you send them a copy of the pieces you need to cut, they can cut them. Could be interesting.

 

Bill

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There's been some good advice.  One thing thoiugh... you might tell us your location as for all we know you're somewhere on Earth and it's a big place with some places having companies that do bespoke work versus places that have zilch.

 

I suggest you go to your profile and add your location.  There might even be someone who's nearby from this forum.

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17 hours ago, allanyed said:

Rio 

Congrats!!  Am I correct in assuming you do not have a scroll saw or coping saw to cut them out yourself?   I am pretty sure there are a number of folks here that will be interested in knowing how you do with laser cutting, including number of bulkheads you will be getting and total cost.  Will you be using your paper plans or will you redraw them first?  

Thanks in advance.

Allan

Yes your correct I don't have a saw that would allow me to cut 5mm ply accurate. I previously build a smit Rotterdam kit in 1/75 scale. I want its running mate in the same scale. So the plan is to resize my zwarte zee plans from 1/100 to 1/75 scale then trace them in a vector drawing program. I can then send the resulting drawing to be laser cut. I have found a local firm but will get a quote once they see the drawings. I'll post my progress and how this goes on here 

Edited by Riotvan88
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9 hours ago, mtaylor said:

There's been some good advice.  One thing thoiugh... you might tell us your location as for all we know you're somewhere on Earth and it's a big place with some places having companies that do bespoke work versus places that have zilch.

 

I suggest you go to your profile and add your location.  There might even be someone who's nearby from this forum.

Thanks for this advice I should have put this in my profile or provided this information. I'm located in Bristol United kingdom. 

 

I have found a local firm but would definitely be interested if anyone near me has recommendations.

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18 hours ago, oakheart said:

I did the frames for my 85 ft Harbor tug on a scroll saw.

 

You can pick them up pretty cheaply locally, our club here in the UK has one looking for a home right now. Shipping would probably cost too much.

Tim

Hi Tim 

I've just had a look at scroll saws and it seems to be the way to go. Where are you in the UK?  I'm also in the UK, South west. I may be interested in the saw your club has for sale 

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2 hours ago, Riotvan88 said:

I may be interested in the saw your club has for sale 

It's an old, no name saw with a cast iron table, single speed and takes pinned blades.
There is a set of adapters to take pin-less blades

 

1050870947_scrollsaw.JPG.0816a1beae8823aadce2b14e6da0df66.JPG

 

It will be expensive to send from Hereford as it weighs a ton ( well about 25 kilos ).
There are 2nd hand saws on Ebay quoting £30 delivery.

I suppose it might be worth £50 ? 

Not having a manufactures name makes it difficult to look up

 

Tim

 

Edited by oakheart
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10 hours ago, oakheart said:

It's an old, no name saw with a cast iron table, single speed and takes pinned blades.
There is a set of adapters to take pin-less blades

 

1050870947_scrollsaw.JPG.0816a1beae8823aadce2b14e6da0df66.JPG

 

It will be expensive to send from Hereford as it weighs a ton ( well about 25 kilos ).
There are 2nd hand saws on Ebay quoting £30 delivery.

I suppose it might be worth £50 ? 

Not having a manufactures name makes it difficult to look up

 

Tim

 

Ok thanks does the bed tilt at all?  Are there no marking or numbers in it at all? 

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Probably better if it did not tilt. 

Once the piece is freed from the stock, another tool could be used to get a bevel and probably do a better job of it.  The end grain of plywood is messy to work with.

 

A scroll saw blade has an unfortunate up/down action.  The blade up can lift the work.

 

The only use that I have for my 9" bench bandsaw is to do scroll cutting.

No up action.  I use a 1/4" blade - it lasts much longer than a 1/8" at only a slight loss in arc. A back and fill cut works as well as a continuous one.

The blade has significant set - the kerf is more - the cut face is ragged - so not too close to the line. ( a sanding drum does a better job of finishing anyway)

The mold could be 1/4" ply or 1/4" solid wood  as it is no problem for a bandsaw to cut

A thicker mold => better planking support

I replaced the guides with a Carter Stabilizer - the blade swings like a hinged door

 

I bet that 1/4" Pine would work well as mold material.

 

Edited by Jaager
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9 hours ago, Riotvan88 said:

does the bed tilt at all?  Are there no marking or numbers in it at all? 

Hi Riotvan, It does tilt. Just checked again - there are no markings at all not even on the motor!

Runs and cuts okay, picking up on Jaagers comment about the up/down problem, there is a sort of hold down fork but no brackets but you could easily cobble something together.

For PnP the size is 55 x 30 x 22 cm and weight is probably closer to 30 kilos, ( my Delta is quoted as 30 k ) 
I could wrap it in corrugated cardboard and bubble wrap.

Parcelforce are quoting £15 for 2 day delivery

 

Should we take this offline, not sure what the rules are on here as I am still a new boy.

Tim

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2 hours ago, oakheart said:

Hi Riotvan, It does tilt. Just checked again - there are no markings at all not even on the motor!

Runs and cuts okay, picking up on Jaagers comment about the up/down problem, there is a sort of hold down fork but no brackets but you could easily cobble something together.

For PnP the size is 55 x 30 x 22 cm and weight is probably closer to 30 kilos, ( my Delta is quoted as 30 k ) 
I could wrap it in corrugated cardboard and bubble wrap.

Parcelforce are quoting £15 for 2 day delivery

 

Should we take this offline, not sure what the rules are on here as I am still a new boy.

Tim

Ok thanks I've had a look online and by the looks it it appears to be a Clarke CSS400 with part of the arm cover missing, the missing part has the make and model stickers. 

53df1c23-e05a-4497-bd49-ab0b00aee95b.jpg

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4 hours ago, oakheart said:

That looks like the one

 

Tim

Did you say it and a clamp or food to hold the workpiece? I'll need to fabricate the missing cover for the arm as that's what the foot mounts to. Looks like a simple U profile sleeve that screws on.

 

I need to check with my work place tomorrow and see if they have the equipment to fabricate that cover. If so I'll be willing to make you an offer. 

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1 minute ago, Riotvan88 said:

Did you say it and a clamp or food to hold the workpiece?

Yes there is a foot with it, have a look at photos of the Delta scroll saw, it just has a rod/bar that is attached to the rear frame, with another rod that holds the foot.

 

I personally never use it, I find it gets in the way, as long as you use your fingers to hold the work down there should not be a problem.

It's just a matter of practice.

also fine blades are better than coarse in keeping the problem at bay.

 

Tim

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10 hours ago, oakheart said:

also fine blades are better than coarse in keeping the problem at bay

With a table saw or bandsaw,  it is important to match the number of teeth with the stock thickness.  If there are too many teeth the gullets fill with sawdust before they exit.  Once the gullets are full the cutting edge becomes a rubbing edge.  From that point on there is mostly heat and perhaps a dulling that is greater than if the blade was removing wood the whole way.  A dull hot blade on a bandsaw snaps.  For a table saw blade it is 3-4 teeth in the cut.  For a bandsaw - a resaw blade is 3-4 TPI,  Bandsaw blades have a deeper gullet - I think.  Given that some saws advertise a depth of cut of 13" or more, the greater volume of gullet makes sense.

To make an extrapolation:  a scroll saw blade may be subject to rules.  Fine blades do not seem to have much gullet at all.  If a scroll cut seems to take too long or the blades break more quickly than they ought,  going with a more coarse blade ? 

 

Now really crap and poor quality plywood may have significant voids.  This would reduce the functional thickness of the stock.  A finer tooth blade may work better than the equation predicts.  But, an additional effect of using a POB mold cut from low density ply with visible air spaces is that the first layer of planking has an even worse bond and the already poor bond provided by end grain.  The whole process may go better if end grain and any voids were first treated with an injection of PVA,  but the PVA not allowed to pool on the surface (wiped smooth), and allowed to polymerize (set) (cure).   If CA is used to bond the first layer of planking,  a test will be wanted to determine if CA plays nice with PVA.

Edited by Jaager
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On 1/12/2023 at 4:37 AM, Jaager said:

It is important to match the number of teeth with the stock thickness.  I

I also do a lot of work on brass using a jewelers piercing saw and the rules are similar with regards to teeth number and stock thickness, every blade manufacturer has a chart.

When cutting wood for model boat making on my old Delta scroll saw I use a medium tooth count piercing saw blade ( will have to check count ) it's very fine compared to the chunky blades normally supplied for scroll saw use.
I tend to use the No. 4 size with 15 tooth count I have gone finer but for wood these are good.

If I can keep it straight, It will cut down the centre of a 0.3 mm  line.

The blades  are good for hardwood, plywood upto about 12mm thick. 

Not so good for ripping along the grain.

see  https://www.cooksongold.com/blog/buying-guide/a-jewellers-guide-to-saw-blades/  for chart of sizes

 

Tim

 

 

Edited by oakheart
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It appears that a decision has been made, but I would like to go back to the original question.  You might be able to look into local high schools, colleges, clubs, etc.  I've become aware that they often accept these types of "jobs" for free, or the cost of the material, as a teaching tool for their students and some clubs will do it as a courtesy or learning experience, even some merchants will do this type of stuff in hopes of making a future equipment sale.  Just a thought for you to consider if you haven't pulled the trigger yet on a purchase.

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