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I am making my own trim (basically casing) out of MDF. The “pre-finished” surface is obviously ready for primer and eventually paint but I’m wondering about the surfaces that I’m creating with the table saw, jointer and router. These surface seem alot more porous. What is the technique for getting them as smooth as the other surface(s). Sanding, sanding sealer?, primer, then paint?
Any experiences and “watch out for”s?
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I usually spray my paint grade projects. I only really use MDF for raised panels. because they do paint nice. here is the process that I use for them,
I sand them to about 180, prime sand(between coats) with cheap fine foam sanding blocks from the paint store the HD dont sell the ones I use. I sand in between coats usually 2 -3 coats of primer then paint 2-3 coats sand in between. Actually it all depends on the surface quality your trying to achieve but thats how I do it.
Just make sure you get all the dust off the material cuz it will show up on the finish. I will blow it off with my air comp. and nozzle real good just prior to prime
*Seal the machined sections with a heavy cut of dewaxed shellac. This closes up the porous surfaces and gives you a real smooth finish
*Like Ron, I sometimes use MDF for paint-grade raised panel wainscoting projects.I use a tack cloth on the milled "raised" portion, then give it a quick coat with a paste pore filler brushed on with a disposable acid brush. Only takes a minute or two per panel.Let the pore filler dry overnight, it sands glass-smooth the next day. Prime and paint.Gotcha's?MDF does split quite easily when nailed too close to the edge. Pre-drilling may be required if you need a fastener near the end of a board. With no grain, some milled edges can be fragile...beads, etc.When nailing MDF, I hardly ever encounter the "volcano-factor" that others seem to suffer. If you do, just pare the lump with a chisel, then putty.The dust will kill you...protect your lungs.
*I have to build a handicap ramp on a friends moblie home. What is the proper rate of climb or angle for a wheelchair? Thanks- Dennis
*1" rise for every 12" of run.Billy
*For handicapped ramps 1 in 12 is the b maximumslope according to AIA (American Institute of Architects). However, 1 in 20 is recommended. A landing is required at every change of direction (corners and u-turns) and every so-many feet of ramp (but I don't have the reference book here with me to quote the distance).Remember, shallower the better for the patient. And, slopes are a hazard for all people in ice and snow.You would also be kind to provide a handrail (without splinters!) at a height the client can reach from the wheelchair. It's also nice if there is no corner (i.e. railing) directly ahead at the bottom in case he looses control of his speed.It's nice of you to use your skills to help out.
*Isn't anyone but me gonna stand up and say that faking wood trim from MDF should be against the law?Arn't we supposed to be woodworkers, not maunfactured sluury of sawdust, glue and whatever they sweep up off the floor along with a bunch of toxic chemicals pressed into a sheet workers?Don't you feel our carpentry ancestors turning over in their graves eveytime a sheet of this mess is sold?Haven't you heard that breathing this dust will make your babies be born naked?Should we call the Woodworkers Guild the MDFworkers Guild?What would Mr. Chippendale Himself say?Don't you feel cheap and dirty using this stuff instead of REAL wood?Are your skills so slack that you can't make a good joint with REAL wood? Are the painters so bad in your area that they can't get a good paint job on a real piece of wood?Do you tell people who see the finished product that it's not real wood, or would you feel funny saying that?I'll bet you'd feel funny saying that. Can you really puff up and say with pride to your customer that there is not a stick of real wood in their house?If you can, then perhaps you shouldn't consider yourself a "woodworker". At least you should show your customer the "warnings" that the manufacturer publishes for this product. I'm sure that will make them sleep better at night.But hey......they saved a few bucks.I feel so alone.Ed.
*Don't feel alone Ed. I posted about this last time MDF was mentioned. I was just gonna ignore this one, but.....MDF is JUNK!!! It's not even a good Subtitute for wood. I don't have time to post a long post, but I think you get my point. No garbage in my house or my clients' houses. You probably will not be happy with MDF for trim, but it's still your choice.Billy
*Billy,I had a feeling you and I would agree on a point or three.No MDF on my jobs.Ed.
*Obviously a sore spot was "touched" based on the editorial you posted. Taken to the extreme then; OSB shouldn't be allowed, even plywood. Vinyl siding! a whole list of materials that are manufactured as opposed to natural read "real".I wasn't asking for the pro's and con's of using MDF as opposed to "real" wood. I had already gone through that process with input from others. This is my own house, I can get the look I want to achieve with this material at a cost which allows me to upgrade other items.There is plenty of "real" wood in this house, but... given the fact that I don't have an unlimited budget, choices have to be made.
*Hey Al,I replied to this in another post.It's your house. Don't begrudge me because I don't share your views.Do whatever you want. Use whatever you want. But don't get pissed because someone here doesn't share your views and says so.That's what this forum is all about.You know, different opinions and view points?We all learn from that aspect.Ed.
*Al:I have used a lot of mdf for custom trim. Although I wish I could use real wood, cost is always a factor. However, I have made some high style moldings and wainscoatings that look none the worse for having used mdf. Sometimes it looks better than real wood. I make furniture using only real wood and I even cut drawer bottoms instead of using plywood. However, I have no problem using mdf for trim that will be covered in paint.Tricks-- believe it or not, I've been able to use low angle block planes to clean up sawn edges and to hand fit raised panels. Otherwise, use sandpaper. I prep the edges and surfaces with Benjamin Moore's Fresh Start primer, and it works well. I always predrill. Avoid sharp edges on door corners as they can chip down the road.One more thing-- to save my back, I sometimes buy pre-cut 12" wide mdf shelving to rip into molding. It's easier to handle than 4x8 sheets and the extra cost is very little.
*Kinda thought you might be lurking Ed :-) I used mdf casings in my home and I will never use it again. But like you said, It's my house and I'm the only one who notices.
*Hey wedge,Yeah, I'm checking in from time to time.You're a lot like me.I seem to learn things the hard way.Regards,Ed.
*Never been called a fast learner. I've been away from the board for a while. Seems like a lot of the usual suspects are gone. I guess you have to hang around just to see what will happen next.
*I would like to add a brick veneer to an exterior wall of a home which presently has siding. The block wall foundation is 10 inches, and the mudsill is built to the edge of the top block. Any ideas?
*ed. and billy...all the more for me..... i love mdf.. mdo... gp primetrim...fibercement.. and vinyl clad windows... steel and fiberglass doors....formica... corian.. ceramic tile...veneer...oh yeah.. and good old fashioned wood...all part of the product...b but hey, whadda i no ?
*Mike,I too like MDO, Corian, Formica, steel doors, ceramic tile, veneer,etc., but not MDF, it's just dust and glue. I don't like particle board either.I like OSB, TJI's and other engineered products. I like steel studs and the list goes on. I can't speak too much for gp prime trim or fibercement ( have not used it much as most of our projects are brick and/or stucco, and stone, etc.) In the lower end market, we have done alot of vinyl siding. We have used fibercement siding however a few times and from what I see, I like it.It is just MDF and particle board. (and MDF is good for a FEW applications, but not for trim throughout your whole house).Billy
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I am making my own trim (basically casing) out of MDF. The "pre-finished" surface is obviously ready for primer and eventually paint but I'm wondering about the surfaces that I'm creating with the table saw, jointer and router. These surface seem alot more porous. What is the technique for getting them as smooth as the other surface(s). Sanding, sanding sealer?, primer, then paint?
Any experiences and "watch out for"s?