|Forum topic by holzbee||posted 03-26-2015 06:51 PM||1538 views||0 times favorited||11 replies|
03-26-2015 06:51 PM
Ive been struggling a bit with what seemed like it would be a relatively easy process of making cradled mdf panels to paint on, but being a newbie I ran into many problems and questions. I wanted to outsource it to a proper carpenter but its out of my price range and am now back trying to see if its possible for me to do it right on my own.
Im looking to do something like the 24×24 panel on this page, but I want to make them around 95×78” (7” 11” x 6’ 6”)
1. The first problem is that when I get my straight and 45 cuts from the lumber store, the butt and corners/45s simply do not line up and my attempts to sand them makes it worse. I hear that the cuts from lumber store are not accurate. What equipment, saw and type of blade (tooth/quality), etc. might I be able to get to get proper clean cuts? I dont have a huge budget, but seems most of the cuts I need for the frame should be pretty basic. The MDF I would get cut elsewhere as those come out fine.
2. I need this to be as light but as stable from warping as possible – its for gallery and museum use and needs to be long lasting. What size/kind of wood and how many cross and diagonal braces do I need to calculate at the above size and smaller. I’m planning on using 1/8” mdf, so this is just for the brace.
3. What other tools might I need to make any adjustments if any, such as planers or belt sanders, etc for the length of the wood and the butt ends – things just dont seem to line up for me. I would like the frame and mdf to be flush all around and for the inner joints to be flush as well. Again I dont have much to invest, but I need to get it right. In the end it will be cheaper then outsourcing it.
4. In my limited experience, the fame didnt lay flush with the mdf and I had to use a lot of wood glue to fill in the gaps. Seems this shouldnt be so difficult, but doesnt work. Not sure if its the wood or me or both. :) What’s the best way to do this? I tried making the cradle first and then gluing it and the other way around.
5. I sanded and wiped with a bit of alcohol the mdf, but then it literally drank all my polyurethane I used to seal it. Is this normal? Did I over sand maybe? (as a side question, Im guessing the varnish goes on after the cradle is glued, but its hard to get in all the crevices without pouring it on, but if I varnish all the pieces before, then it doesnt stick good and my attempts to sand the varnish first to give it tooth resulted in my not being confident that all the surfaces were varnished).
Thanks for any advice or links to how to do this right.