mdf glue joints

UKworkshop.co.uk

Help Support UKworkshop.co.uk:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

geoff_tulip

Established Member
Joined
13 Jan 2004
Messages
79
Reaction score
0
Location
northern ireland
i have laminated up a block of mdf using pva which has been sanded - and i want to paint it. in trials i am still getting the glue lines showing through the paint after many coats. it is important that these are not visible. i didnt use mdf sealers but plenty of coats have been added - both acrylic spray and emulsion give same results.

any experience with this and suggestions ?
 
Are you cutting the block to size afterwards or are you just glueing it together then sanding. If you glue it together over size then trim to final size and sand, the glue joint shouldnt show if you have done it well.
 
the block is glued - then cut - and then turned and sanded - so finish should be ok.
i have said that it is the glue line - but i should have said that it was the joint region - ie perhaps the treated top and bottom faces of mdf may be the problem. i also should have said that there is a paper joint between the mdf sheets to allow for easy separation which may also be an issue.
 
The key to the problem, I think, is the use of water based finishes over PVA. Give it a coat of shellac prior to painting and you should get an even coverage. If you haven't got shellac use button polish or sanding sealer it's all based on shellac anyway.
Rob.
 

Latest posts

Back
Top