About six years ago I built a curly birch work desk for LOML. I wanted a heavy duty scuff resistant finish that could stand spills, condensation from a glass, and moving the adding machines and keyboards across it.
I pretreated with 1/3 turps - 1/3 tung - 1/3 3# shellac to light up the grain and let it dry overnight.
Then I thinned down polyurethane (don't remember the maker) satin finish by about 10% and padded it on. I put on 5 thin coats over about
3 - 4 days, and it has worn like iron. It looks as good as the day I put in in her office with no special care at all.
I would also recommend polyurethane. As for the oil primer, I feel this needs to be sampled. Some time oil darkens a timber more than PU, so if I want a blonde appearance I will not put boiled oil or oil/vege-turps mix on. Other times, when I want to enrich a contrasty dark timber I will make a point of it. In other words, I heartily recommend doing some samples on scraps or inconspicuous places and see which look you like best.
I sometimes also use a receipe that I found in Fine Woodworking Mag some 20 years ago - 3 parts vege turps, 2 parts gloss PU, 1 part boiled linseed oil. (gloss pu because matting agents can interfere with the mix) and this you flood on, then wipe off excess once it stops soaking in. Rinse and repeat several times. It will darken and enrich the grain, it will also fill pores and harden the wood and you can later paint or spray satin poly over the top without problems. I've used other kinds of Teak - or Scandinavian Oil finishes as well as concoctions w. Tung oil and they all come up different. You really have to see how YOUR particular timber reacts with the concoctions you have, and then judge by your taste. Basically speaking: turps thinned polyurethane should go over oil based finishes without problem.
I recently did a computer desk for myself from Rimu and Taraire, the Rimu carcasse and doors I did with the oil, the blonde&black hard Taraire I just did with 3 coats of PU; first one slightly thinned - looks great and is impervious to anything in the way of coffee and beer I've been able to do to it the last 6 months :-)
I would like to know how you are planning to fasten the pine to the MDF (or plywood)? The pine will "move" with humidity changes and the MDF will not seems as if this could cause a problem.
Russ "Lobsang Mack rogers com>" I am in the process of building a new computer work center.the top will be
I would like to know how you plan to fasten the pine to the MDF (or plywood)? Seems like the pine will "move" with humidity changes and the MDF will not.
Russ "Lobsang Mack rogers com>" I am in the process of building a new computer work center.the top will be
I don't think I'd be comfortable with a lamination of 1 mdf and 1 ply either; if you want to do that combo you'd be better off using a sandwich of 1/8" ply,
3/4"- 1" MDF and another 1/8" ply. Take a bit of clamping though. In fact you'd probably be better off buying veneered MDF in that case. (that's what I use for the panels in frame-and-panel these days).
Alternatively if you go with 3/4" ply as you proposed(?), you won't need much extra support at all while the desk is up to 2'6" wide; otherwise I'd suggest gluing small strips of solid wood underneath that tie into the carcass of the desk.
A single layer of ply with a single layer of MDF is bound to end up looking like the Sydney Harbour bridge eventually.
1/2 plywood, mdf adds weight but not much strength in my opinion. I've never seen knotty pine plywood for sale in a lumber store, here we just use the solid stuff.
I would rethink the use of knotty pine. I wouldn't use knotty pine on any desk surface, it is just too soft and you will have dings all over it 6 months even if you are moderately careful.
Lobsang Mack Sorry....3/4 knotty pine ply with 1/2 mdf backing it........total 1 1/4
I don't know what species your 'knotty pine' is, I'm in a different part of the world :-) some of the plantation pinus radiata that we get here in New Zealand can be so hard you can't get a 4" nail into it -- if it's well milled and seasoned. Much of it is as soft as warm butter, though. I can tell by the weight and the looks.
Maybe I did not understand what you are planning. My question assumed you were going to use 3/4 by 4 or 5 inch wide pine boards over MDF. If that is the case the pine will expand or contract in width while the MDF will not. If you glue and screw the boards down they may cup.
Russ "Lobsang Mack rogers com>" I was planning on glue & screw.....any other suggestions?
HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.