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Biscuits and Plywood

2K views 10 replies 8 participants last post by  Al B Thayer 
#1 ·
So I had bought a biscuit joiner a while back for the sole purpose of using it to install a deck using those hidden fastener systems. Now what do I do with it? I've read in a couple threads that they are okay for plywood joints. I've always used dados and rabbits. I want to outfit my shop with more storage options, nothing fancy though. Am I going to be severely disappointed with biscuits or will I be happy with the time I can save. What ways are acceptable to join plywood using biscuits?
 
#2 ·
Whether you are happy or disappointed will be hard to predict. Biscuits are lampooned by some, and revered by some. I happen to like them, believe they add strength in some joints, and are really useful for aligning edges on panels. I've also used them on plywood with good results. The downside that can happen (and can be prevented) is that the biscuits swell, and this sometimes leaves a bulge on the surface of a panel. If you sand it flush, the wood will subsequently shrink, leaving the impression of a biscuit on the surface. Waiting for the bulge to shrink, or putting the biscuit off center on the bottom of the panel can solve this. The alignment thing is especially useful when putting face frames on cabinets. All this, of course, is just my opinion, and many will tell you to chuck the thing.
 
#3 · (Edited)
I've never used them on plywood and would be concerned because of the nature of plywood to split into the various layers of it's laminates. If you are butting joining plywood of similar or identical thickness, I would use a full length spline of hardboard or hard wood.
A butt joint is not the best method. A half lap or opposing rabbets would be better...test pieces required for an exact fit. :yes:
 
#5 ·
Biscuits certainly will add strength to the joint but if you think about a #10 biscuit is only 2" long and for the 2" makes a great joint however the six or more inches between them are just a butt joint. An easier way to make a great joint all the way down is to use a full spline.
 
#6 ·
Biscuits are great. Some the old timers do not like them and that is ok. I mainly use them for alignment when. When I do my rope corners I have to glue solid oak to plywood and they work great. Forget the, OH they will swell and split the wood, does not happen. I have put many joints together with them.
That said there are other ways to do fine furniture joints. But for me to make money and build cabinets and compete they are the way to go. Why would I spline a joint when I can biscuit it in minutes.
LOL, I know I am going to hear about this, so be it. I run my shop to compete and make money.
 
#7 ·
Biscuits are ok for what they are. Will not produce as strong a joint as dados & rabbets or a full spline for that matter. But they do have their place. In a production cabinet shop they are a perfectly acceptable method of joinery. In custom cabinetry & fine furniture making they have no place. Just my opinion.
 
#8 ·
I use them when the project doesn't warrant high cost joints. I put a torsion box bench top out of MDF together with them. They have more strength than many dowel joints and require less time. I never do dowels anymore. I don't replace them with biscuits all the time. Just when it's a low cost project. I hate dowels.

I also don't understand how they aid in alignment. I have a Porter cable tool. It cuts a slot that is forgiving in size till the biscuit swells. Won't help me align anything. Maybe that's why I have never had a problem with swelling. But then I don't have a problem with alignment because I face all my boards in preparation of glue up.

For the guys that don't like them. Do you have a biscuit jointer or are you trying to use a router. Because without the tool it would suck bigtime.

Al

Friends don't let friends use stamped metal tools sold at clothing stores.
 
#9 ·
Steve Neul said:
Biscuits certainly will add strength to the joint but if you think about a #10 biscuit is only 2" long and for the 2" makes a great joint however the six or more inches between them are just a butt joint. An easier way to make a great joint all the way down is to use a full spline.
Do you know they have a 20 size too?

Al

Friends don't let friends use stamped metal tools sold at clothing stores.
 
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