lam prep ?

soy · April 29, 2014, 06:38:00 PM

when building wooden tri lams and using urac I scored the wood so to speak with a hack saw blade or a toothing plane the full length... what are the pros and cons of doing the same in a glass bow in the wood lams using smooth on???

LittleBen · April 29, 2014, 07:12:00 PM

This is interesting. I've always just used the sands surface of the lams as is. I do wonder what the glass guys are doing

Roy from Pa · April 29, 2014, 07:15:00 PM

I doubt if the glass guys do anything to the lams. Like you said, Ben they already are roughed up from the drum sander.

jsweka · April 29, 2014, 07:21:00 PM

Just brush any dust and dirt off with a stiff brush and glue it up.

Some guys wipe with acetone or heat the lams up in a hot box first. I don't do either and never had any problems.

beachbowhunter · April 29, 2014, 07:23:00 PM

I use a wire brush, then the air compressor to get the dust off.

Troy D. Breeding · April 29, 2014, 07:24:00 PM

x2 on what jsweka said

kennym · April 29, 2014, 07:56:00 PM

Yep, just brush off, blow em off with clean air and let the glue fly!

soy · April 29, 2014, 08:21:00 PM

That is what I have done so far....but I have a bow someone wants with a 33" draw @70#

was wondering if it would be a benefit to increase the gluing surface ??? Also would 70" ntn be long enough for that DL?

kennym · April 29, 2014, 08:27:00 PM

I think 50 grit surface would be fine, cause the glass isn't any rougher than that . If a D/R bow , 70" would be plenty, probably 66" would work on my design.

If a Hill style...ask Jsweka! LOL

bornofmud · April 29, 2014, 08:28:00 PM

Depends on the shape and riser length I think, but sounds about right for most shapes. Maybe reduce the taper a bit if it's a straight d shape. Also, I do the same thing the guys above stated, just brush and maybe denatured alcohol if they got dirty for some reason.

snapper1d · April 29, 2014, 09:56:00 PM

I cringe every time I see someone say use a hacksaw blade or toothing plane.What do you get with those? You get a roughed up bunch of broken splinters that you can not possibly get glue down into all those cracks.SmoothOn and all the glue people have done more test with their glues than any have done bow glue ups.They test constantly and have found that clean sanded surfaces will hold better than any torn up splintered surfaces will.Splinters are just that.Broken fractured wood!!!

bornofmud · April 29, 2014, 10:27:00 PM

Yeah, I was taught to have a clean sanded surface for glue ups, never much understood roughing up the surfaces more than that.

soy · April 29, 2014, 10:32:00 PM

QuoteOriginally posted by snapper1d:
I cringe every time I see someone say use a hacksaw blade or toothing plane.What do you get with those? You get a roughed up bunch of broken splinters that you can not possibly get glue down into all those cracks.SmoothOn and all the glue people have done more test with their glues than any have done bow glue ups.They test constantly and have found that clean sanded surfaces will hold better than any torn up splintered surfaces will.Splinters are just that.Broken fractured wood!!!

That speaks volumes!!!!! Thank you all

Roy from Pa · April 30, 2014, 08:32:00 AM

I have read where a hacksaw blade is not a good idea because of the lay out of the teeth. However I have used a toothing plane for 10 years now on my BBO bow glue ups and I have Never had a glue joint fail. I'm equally sure that the wood gets pretty ruffed up when those lams are ran through a drum sander with 60 or 36 grit paper. Just sayen.

spider1 · April 30, 2014, 10:33:00 AM

it is all going to depend on the type of joint that you are gluing and the type of glue you are using. Urac 185 fills voids very well while smooth-on doesn't. With some glues like Urac a starved joint is something to avoid. You also don't need to think too much about small splinters on the surface, it is just more material for the glue to hold to, it soaks into tiny fibers and surrounds them and adds to the strength. One thing that you have to remember, the original purpose for a toothing plane was to prep wood for laminating. I've seen bow glue ups that have been prepped with a toothing plane and those that have been prepped by leaving smooth with just sanding marks and degreased. Most of both type of glue ups have resulted in fine shooting bows while I've seen a few of either come apart under, shall we say, duress. But in no bows that I personally prepped with a toothing plane have ever deleminated, I have had one glue up that I tried without prepping this way delaminate due to what I believe was a starved joint. Maybe I tightened the clamps too much or my glue mix wasn't right (I doubt it) but I prep my laminations because that always seem to work best for me.

spider1 · April 30, 2014, 10:56:00 AM

one more thought, more to the point of your question. Smooth-on doesn't like gaps or contaminants in a joint. As stated by other guys, it would be best if using smooth-on with laminations to not prep the laminations with a toothing plane. jmho

spider1 · April 30, 2014, 10:57:00 AM

one more thought, more to the point of your question. Smooth-on doesn't like gaps or contaminants in a joint. As stated by other guys, it would be best if using smooth-on with laminations to not prep the laminations with a toothing plane. jmho

Roy from Pa · April 30, 2014, 11:04:00 AM

Ah what's a machinist know about wood glue?

snapper1d · April 30, 2014, 11:32:00 AM

If you were hanging on a limb would you rather hold onto one that was splintered? Seriously,even urac cant get down into the micro cracks down in splinters.Splinters are just broken wood.

spider1 · April 30, 2014, 11:44:00 AM

micro cracks? have you ever used a toothing plane? micro cracks.

Hi Roy! How ya doing! Build any kiddy bows lately