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Main Boards => The Bowyer's Bench => Topic started by: kenboonejr on July 03, 2021, 08:56:05 PM
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So I bought my take down recurve bow kit like 4 years ago, right after I made a red oak board bow thanks in part to this site and started a few other board bows. Then I hurt my left shoulder and had to have surgery. I recovered from that then got a SLAP tear on my left shoulder and had to recover from that. Once that got back to normal my right shoulder went bad and had to have surgery on that. So now I am back to 90% and decided it was time to make this take down recurve. The kit has been stored in the box it came in 4 years ago in my office so it has been in a temperature controlled environment. I finally opened up the kit this weekend. So here are my questions?
The kit came with Smooth On part A and part B. Do you think this is still good after sitting on the shelf if you will for 4 years?
The metal strip that will be used in the form when glueing the laminations together has somewhat of a sharp bent/dent in it about 1/3 of the way down it. Will that flatten out and be ok once pressure is applied in the form or should I get another one?
Last question. I know lumber has gone up, but I myself have not been out to purchase lumber. The heat box plans call for two 4x8 sheets of exterior plywood 1/2" thick. I went to the store today and they were $71/sheet. I knew prices went up but I didn't realize how high. Just wondering at those prices can I step down to OSB? or something different even? Just wondering on what your thoughts are on that. I would assume OSB could hanldle the heat that will be put in it. At least that is my assumption. Although the OSB is only slightly cheaper than the plywood.
Thanks!
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get some New smooth on, get the smallest one, you can hammer out the dents on the pressure strip and file and sand the sharp edges :thumbsup:
Smooth-on will cure at room temp. 70* in 24 hours and that will be fine, if your truck is hot inside it you can put your form in there to cure, 140* ish maybe, according to where you live. don't forget to put down some cardboard or old blanket to protect your truck from the smooth on drippings. You can wait on making a hot box until later, some do not even use one.
Some use a electric blanket around the form and maybe more regular blankets over the top of that to hold in more heat. Poke a thermometer threw the electric blanket, even at 120* will work for 8 hours or so. :thumbsup:
put 50psi. in your fire hose and stick each end in a bucket of water to check for leaks.
Last thing , Take your time
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I would replace the Smooth On. It may be ok and then again maybe not!! Save it for repairs around the house 🏠.
The dent in the pressure strip is not a problem.
You don't need an oven at all. Smooth On will cure in 24 hours at 72 degrees. Options to speed it up; put it in a car in the hot sun; wrap black plastic around it and put it in the sun; throw an electric blanket over it. I've done all of those without problems.
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Max, you type faster than me! 😀
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@Mad Max @Longcruise
Guys,
Thanks for the great responses. I will take your recommendations and get some fresh smooth on! That's a relief that I don't need to build the hot box. I just couldn't believe those prices. Still need to go get some wood for the form though. Hope to get that today and get started on the form. So worst case scenario is it will cure in 24 hours where I am (SC) or I was thinking about the comments you guys made about my truck. I'm gonna throw a thermometer in the bed of my truck which is covered by a black aluminum bed cover and see how hot that gets. I guess that leads me to one additional question. Everything I have seen on heating these forms always shows the forms standing up. Once everything is locked down tight is it okay to put them on their side - like if I do put it in the bed of my truck?
Thanks again!
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My 5 year old hunting bow was cured at 70* on the bench just to see, no probs with it yet but I don't expose it to a lot of heat. I had heard some bowyers weren't heating so I had to see. The thinking is if you heat the cure, the bow will stand more heat after without delamming.
That said, I cure them all after that. Overlays I never heat,and use the older glue on sometimes , they can be put back on unlike the limbs.
Smooth on has a 2 year shelf life now also.
Form on it's side is fine.
Good luck and have fun!!
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Kenny is right you need to heat to have heat resistance from hot cars deer blinds or just plain hot days at the range . Any epoxy you heat cure will be stronger . I reheat mine usually twice but with some bows and more overlays they may go back in 5 times although not as hot as the first cure .
I talked to the chemist from smooth on and he said you can reheat up to the original cure and and it goes back to the same strength after it cools.
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Guys,
I appreciate all the good info. I purchased the wood for the forms today and placed an order for some fresh Smooth On. Hoping to get the form built in the next few days and by the time that is ready hopefully the Smooth On will be here. I am going to temp check my truck bed and see how hot that gets and try to use that method I think. Thanks again I'm looking forward to getting this going.
Thank you!
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I'm sorry one more question.. ;) So I know I can call Binghams and ask them this but I figure they are probably closed tomorrow and then I would have to wait until Tuesday evening to start. See where I am going? Anyway, my bow build is for a 1.75" bow, so the lams, pressure strip etc is 1.75" wide. The instructions only talk about building a 2" form. I know I have read stuff here where it seems like folks build the form to the exact size of the lams. So do I move forward with laminating plywood together to form a 2" form or do I need to make sure it is 1.75" I "think" I would need to do 1.75 but figured I would double check with you guys.
Thanks again!
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1-3/4" is what you want :thumbsup:
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Thanks Mad Max! Plan to get them glued up tomorrow!
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Also, for each glue joint or sheet that you use to get to 1.75", you will lose 1/32". It's not much but depending on how many sheets you glue up it will add up.
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What do you recommend then as far as size of plywood sheets to glue together. It seems like my only option is to use one 3/4" and two 1/2". So I will be 3/32 short of the 1.75". How critical is that or is there a different way I should be doing this?
Thanks again!
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Others will recommend against it but, I have had great success using MDF. You need to protect it from moisture I also skin it with thin plywood. The thickness it comes in are very close to the actual thickness unlike plywood. Another option is using LVL, I haven't personally used it but others have had great success with it. Good luck on your build.
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I use roofing felt as a filler. That may not be ideal. There may be better ways of handling it. I do it that way because I have it on hand.
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Yea I figured if I oversized it and then tried to plane down the plywood that that would not go well. I'm gonna look around in my barn and see what I can use for filler.
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All plywood does not actually measure what it says take your calipers to the lumber yard with you see what you can find Don't forget about 1/8 inch hard board as a spacer. Or the thinner plywoods but take your tape measure and calipers and measure up see what you can come up with. JF
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This is what I use for a filler...
https://www.homedepot.com/p/Ram-Board-042-in-x-38-in-x-50-ft-Temporary-Floor-Protection-Board-5008195/202829135
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This is what I use for a filler...
https://www.homedepot.com/p/Ram-Board-042-in-x-38-in-x-50-ft-Temporary-Floor-Protection-Board-5008195/202829135
X2
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LVL is the way to go. No gluing and screwing plywood involved. All of my forms are LVL sandwiched between two pieces of 3/16” angle iron and bolted together to assure it stays straight over the long term.
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Turns out my daughter had some left over ram board from some craft project she worked on. Not only that but I had all the correct lumber I needed in the barn already leftover from some cabinets I built. Turns out 3/4" ply plus two 1/2" ply plus two sheets of ram board hit 1.75" right on the dot. I got everything cut to size and then started working on tracing out the templates from the plans Bingham provided so I don't have to cut into their plan sheet. Hopefully get the form built tomorrow. Thanks for all the suggestions guys!
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I would sure use the router method on the form. It is so much easier to get good flowing lines on the limbs by sanding a template to smooth lines. Waaay easier to sand a quarter inch template than a 1.75" form.
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Yea that makes sense. I'll have to assess what I got for doing that tonight when I glue up the form. Thanks!
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What Kenny said, I myself only make a little over half the template then flip it over to do other half of the form that way you know both limbs are the same. A good form is most important.
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What Kenny said, I myself only make a little over half the template then flip it over to do other half of the form that way you know both limbs are the same. A good form is most important.
Absolutely, the form is for sure an important part!! This one is a TD but I also use a half template on one piece bows.
Of course you could make both limbs at the same time on a double ended form with a template and have exact match...