Fastening Wood Edging to MDF
Advice on fastening 3/4" by 3/4" solid wood to the edge of an MDF panel. Is anything besides glue required? August 29, 2006
Question
I would like to glue 3/4" x 3/4" stock to MDF sheet goods for a top of a bench. My question is do I need biscuits or splines, or will glue be strong enough?
Forum Responses
(Cabinetmaking Forum)
From contributor A:
It depends on the usage. MDF holds glue fairly well, but I can't say as well as a wood to wood joint. If you have the capability of using splines or biscuits (with or without jelly) then do so (splines being more desirable). If you have none of those capabilities, just use a good glue like Titebond II and shoot good finish nails and putty them in.
From contributor B:
I have to disagree with what contributor A says in regard to splines and biscuits. Splines and biscuits in this application are not likely to significantly improve joint strength, and may actually weaken it. To answer your question, yes glue is strong enough. I would use biscuits only if it helps with alignment of the two pieces.
From contributor C:
I agree - skip the nails - they weaken the edge. Do a good job of glue and clamp with Titebond original.
From contributor D:
For the top of a bench I don't think glue is enough. A 1/4 x 1/4 tongue on the MDF and 1/4 x 1/4+ groove in the solid would be stronger. This increases gluing surface and therefore the strength.
From contributor A:
I have had fairly good luck using pocket screws and glue to apply edging to melamine. I would think it would work on MDF as well.
From contributor E:
A tongue and groove as contributor D suggested would in fact make a dramatically stronger glue joint, but there's so little material left surrounding the joint the whole thing would be structurally weaker - especially in MDF - which I think was contributor B and contributor C’s point. When gluing solid to MDF/PB edges, just remember to pre-glue the MDF, sizing the joint. Pre-glue it, let it soak in a few minutes, then re-glue it, clamp, clean, etc. It'll hold fine for a long, long time.
From contributor D:
When you glue to an MDF edge it is like gluing to end grain. The strength of the piece is enhanced with the tongue because now you are also gluing to long grain. It’s the same reason a lock miter is stronger than a flat miter once glued. You don't have to believe me - try it for yourself. Take two 3/4" square pieces 12 inches long and glue them both ways, then take a hammer and see which one you can knock off easier.
