Are there any decent clamps?

[bigcreekdad]

I'm sure everyone has seen, and maybe used, those red handled and tipped clamps. I'm sure many will agree they are junk. The protective tips eventually will either come off or west through. They also have varying degrees of tipping power....some much tighter than others . AS such, they become useless for things like planking as they end up leaving dents.

 

Are there any really good small clamps out there. I would pay for quality, but haven't seen any. such thing. Any thoughts?

[Dziadeczek]

After all these years I found out, that if I properly spill and heat bend my planks off the model, I don't need any planking clamps afterwards. The planks should lay on the bulkheads almost perfectly, you only need to gently press them in place. For this I use ordinary sewing pins, sometimes those with colored heads. I gently tap them into a bulkhead with a small jewelry hammer, maybe two or three times - just enough to hold them in there, placing the tip of a pin directly under the edge of the plank, NOT THROUGH IT! That way, I don't end up with a hole in the plank, but rather a small hole In the bulkhead (which will be covered by planking anyway, so it won't be visible).

This is my old model of the MS Rattlesnake, showing this process.

Edited February 21, 2021 by Dziadeczek

[druxey]

Elastic bands and blocks are also a good way of holding planks in place.

[TBlack]

How deep does the throat have to be for your needs? I use alligator clamps with the teeth filed down for detail clamping.

[bigcreekdad]

I may have misled....I only use clamps for planking above the wales, and for bending and drying a plank to fit the curve of the bow.....these are the times that I get the dents from bad clamps. I also use clamps on wood for many other tasks when ship building.

 

I'm really just wondering if anyone has a source for good quality small and medium clamps.

 

Thanks

[TBlack]

So you need downward pressure against the wale and inward pressure against the frame/bulkhead. I use those alligator clips for the downward and elastic bands for the inward. Cheap and plentiful.

Tom

[FlyingFish]

 

[allanyed]

Big Creek

 

Per the posts from Dziadeczek and Druxey, you don't need clamps.   Pre taper each plank, bend by spiling (see the article here at MSW by David Antscherl) or just using heat as demonstrated by Chuck Passaro in his article on forming the bends and there is no need for clamps.  If you still want some security while the glue sets, soft wood blocks and elastic bands as Druxey mentioned is a great way to go.  If you are worried about dinging the plank place a piece of felt between the block and plank.   

 

And if you still want really good quality and versatile clamps, you are best off making your own.   Do a search of Ed Tosti's build logs as he uses his own home made wooden screw clamps and may give some details on making these in the logs.  If not, he goes into detail on making these in Volume I of his book on the Naiad.    You can make them with throats and jaws as small or large as you want.

 

Allan

 

[Roger Pellett]

Allen,

 

It is my understanding from reading posts here and elsewhere that the bond strength of PVA Glue is dependent on clamping pressure.  More is better.  

 

If that hat is true, it would seem that some clamping pressure would be desirable.

 

Perhaps readers with a better understanding of glue chemistry than me (none) will weigh in.

 

Roger

[allanyed]

Roger,

Based on looking at various information on PVA  glues recently,  the following is my understanding.   The glue thickness is critical to the strength of a joint as much as the clamping pressure.  It's a function of how well the joint is prepped and how snug and uniform the joint is held together while it begins to cure. The glue line should be about as thick as a sheet of paper or a LITTLE thinner.  Too thin from clamping too tightly will starve the joint and it will be weak.  The more the clamping, the weaker the joint.   By the same token too much glue will also create a weak joint and  the weakness grows with the thickness of the joint.   So, as with many things in life, too little or too much are not desirable.   Sort of like Goldilocks,  it needs to be pretty much just right!! 

 

I cannot argue this point scientifically as I am not a  chemical engineer but I have never had a piece of pre bent wood separate using PVA and finger pressure to hold the pieces together for 30 seconds to a minute as there is enough initial tack to hold the pieces nicely.  Obviously I do not have hundreds of years of history, but as to pieces coming apart so far so good 😀   I recently saw a model that I built in the late 1970s and it looks the same as the day I finished it.   By the same token there almost always seems to be a few areas that need coaxing with clamping.  Unfortunately  it seems these are most often in a position where a stock store bought clamp cannot fit so elastic bands and home made devices come into play.    

 

Allan

 

  

[Roger Pellett]

Thanks Allen.  I barely made it through freshman university chemistry.  I was happy to get a “C”.  The instructor either felt sorry for me or more likely didn’t want to see me again.  I’m certainly not qualified to dig into the details of Glue chemistry.

 

The effect of glue thickness on joint strength is interesting.  I tend to instinctively believe that if a little works, more should work better.  In the future I’ll be more restrained in my clue application.

 

Roger

[Jaager]

On wood to wood, I use a complete just wet covering of PVA of both surfaces, no puddles.  I think it is unlikely that wood would stand up to a clamping pressure that would starve the joint with out damaging the wood itself.  A small version of a sponge stick or an economy artist's brush spreads to PVA.  PVA bonds by a chemical reactions growing long chains that intertwine and grow into the irregularities on the wood surface.  This why having too smooth a surface is unwise.  The closer the two wood surfaces, the less of a zone of just plastic tendrils intertwining with each other there is.

Completely reacted PVA is flexible rather than rigid, so too thick a joint may have slight movement?

Metal to metal, I can see being able to squeeze out most all of a glue.  Maybe  with a 400 grit or 600 grit or finer finish, too much PVA could be forced out.

 

I favor hitch chocks for planking, but that involves follow up trunneling with bamboo to fill the holes, or nipping off the brass pins, if you favor that look.

[AON]

Not to be funny... I find all clamps are very good until you need that special one... like right now.

[Duanelaker]

Clothespins are cheap?  Not too much pressure, easily modified.  They do sell alligator clips without teeth, as well as I have seen people put shrink wrap over the teeth.   I also have been finding that even with PVA, finger pressure for 30 seconds will hold pretty good as long as there is not too much force in the other direction.

 

I will agree clamps work great until they can't get to where you want them, or hold the piece properly....

Edited February 24, 2021 by Duanelaker