HDBRbuilder Posted November 16, 2002 Share Posted November 16, 2002 Tom, Varathane is/was the brand name of the polyurethane made by DuPont(the same folks who supplied gunpowder to both sides of the European theater during both world wars...but that's another story!!)...it was the first one out on the market. Once DuPont's patent went out...the other paint makers jumped on the wagon and the price dropped considerably, as usual!! I used to be kinda partial to the Red Devil brand, but haven't seen any of it around much in the last few years. Now I use the Minwax stuff...but I am still partial to the oil-based type of polyurethanes. They dry faster and it doesn't bother me any to have to use mineral spirits for clean-up. There is very little difference in Polyurethanes that have the same base to them, so it doesn't really matter much which brand you use, but if you intend to use a urethane with a stain or color added, and it will take you MORE than one can of it to finish what you are working on, then by all means use one from the same manufacturer and check the lot numbers on the can to ensure that you are geting multiple cans from the same lot...because there will likely be at least some little bit of variation in the mix if you get cans from different lot numbers. More and more people are going to water-based urethanes, but since urethane is a major dust magnet while it is wet, I prefer the faster drying oil-based ones. Water-based is easier to apply, and it isn't as finicky in the brushes used(and can even be applied with a rag if you want), but the faster drying of the oil-based type is worth its weight in gold as far as dust goes. One thing about urethanes in general...whatever they say on the can about the amount of time you need to wait before scuffing and applying the second coat...multiply that time by a factor of 1.5 to get the best results...especially on your sealer coat. The sealer coat takes the longest to dry, and usually takes the most finish to get a good coat...because it is sucked up by the wood fiber. Successive coats will take much less time to dry because part of the thinning agent in them is partially absorbed by the previous coat. Another thing aboput urethanes is that they never completely become a solid...kinda like glass never completley becomes a solid. Over time, gravity will cause the urethane to become thicker at the bottom than at the top, but it is a microscopic difference...same as in glass...unless that glass has been a window pane for a couple of hundred years...LOL! One of my tricks of the urethane "brush-on" trade is using one can of urethane, one brush, and one can in which I put the brush to clean it for just the sealer coats. This is to eliminate any contamination of the final coats with grit or sanding dust that may still be on the project when I first apply the sealer coats to it. I always use new brushes, a can of finish JUST for the final coats, and a clean can just for those brushes...when applying the final coats. It may seem anal retentive, but I have found that it really DOES make a difference in how nice the final product turns out!! I don't use a tack cloth before applying the finish, instead I use a nice paint brush to "sweep the grain...running WITH the grain"...after using compressed air to blow off any dust. So far I have had great luck doing it this way...and my finishes are nice and smooooooooooooooth! It is important to do everything possible to eliminate dust particles from getting into the urethane as it dries. This doesn't mean you have to be in a dust free environment, but it does mean that you need to eliminate any possibility of dust getting stirred up into the air when doing the finishing...to include not having any heater or air conditioning blowers at work around you...hint hint!! Also, walk carefully and DON"T shuffle your feet...stay away from a carpeted floor to apply the finish...carpet is full of minute dust particles...every time you take a step, it puffs them into the air from the carpet!! No kidding!! LOL! Be deliberate but SLOW in your movements...that way no dust gets stirred up. Sound like a pain?? IT IS!!...but the results are worth it!! the best time to apply a urethane finish?...especially the final coats? Late at nite...after everybody has gone to bed...and on the day after a good rain when a cold front(dry air) has come in...less dust to deal with that way...and the drier air gets the finish to tack-up sooner!! Be sure to wear clean clothes when applying the finish...and wait awhile after doing any sanding so that any dust from that has had time to settle out of the air. Oh yeah...wherever you used tha tstripper, wipe the speakers down with mineral spirits before your final sanding...it shou8ld get most of that stripper residue off...if it doesn't do so, then you may have to use acetone for the wipe down...different strippers rewuire different things for the wipe down...and there are a zillion of different kinds of strippers...there should be some directions for the wipe down after using the strippers on the can...but they are often gobbly****ed up with wording like: "be sure to use our (insert brand name here) wood preparation cleaner after the object has been stripped of its finish, prior to using our (insert brand name) finish." You will have to go read the ingredients on those cans to see what "their prep solution" really contains...and save yourself some money by just buying "Brand X" of that particular prep solution...normally mineral spirits or acetone or something like that. No need to buy that "no odor" or "low odor" mineral spirits for brush cleaner either...it is just a way of the companies to get you to paying three times as much for the same thing, just because it doesn't have an odor...LOL! Since the chemical evaporating into the air is still mineral spirits, the no-odor part is all you are paying for...it is still evaporated mineral spirits you are inhaling...LOL! Your nose just can't tell it!! LOL! At least when you can smell it, you can tell if you are getting TOO MUCH into you!! LOL! As for acetone...it has many uses besides a thinner for laquers and a cleansing agent. Such as: The next time you know of somebody who has gotten a case of athlete's feet...just tell em to throw away all of their athletic shoes(because the spores of the fungus will NEVER be removed from them), wash all their socks in hot water with twice as much bleach as they would normally use for their whites, and throw away their colored socks...then before wearing any new socks, new athletic shoes, or the clean socks, scrub their feet extremely well using lots of soap, and the hottest water they can stand...rinse them off well, again in the hottest water they can stand...pat them dry...and soak them in acetone for at least 15-20 minutes...it may hurt like hell if they have had a bad case of athlete's feet(no pain, no gain!!)...but it will kill the hell out of the fungus and bacteria...and will render the spores of such unable to germinate...end of the problem!! LOL! Trust me on this...I have never seen it fail, and it is MUCH cheaper than all of that goop and foot powder they sell to get rid of the condition!! Quote Link to comment Share on other sites More sharing options...
Tom Mobley Posted November 17, 2002 Share Posted November 17, 2002 HDBR, Thanks for taking time to write up that stuff. A lot of typing. I pulled the back off one of the speakers to install the little wing pieces that run from the corners of the 3x13" slot to the corners of the motorboard. I used it for a sample or trial piece, one side I sanded the finish off, the other side I used the stripper and scraper, then sanded. The scraper is tricky, I made little tiny line gouges where I wasn't careful enough using it. I went out tonight to HD and bought Minwax Tung oil and Minwax clear satin polyurethane, did half the back with each. Only one coat so far, but right now I would have a hard time telling which is which if I didn't already know. Seems crazy, they're not really similar products. Both of them are darkening the wood much more than I had hoped. I don't know how to retain the blondish/whitish character of the sanded oak. Looks like it might take just spraying with clear lacquer or something. Did you ever post a pic of your finished units? I'd like to see how they turned out. Wish I had the money to buy a set. Tom Thanks again for taking for that write-up, very informative. Quote Link to comment Share on other sites More sharing options...
HDBRbuilder Posted November 18, 2002 Share Posted November 18, 2002 Tom, I thought you had completed your LaScalas already. Have you? The reason I ask is that none of the parts you have mentioned should have been removable. Did you build your wings as units?...meaning, gluing and securing each assembly PRIOR to installation? What angle miters did you use for them?...it should be 60 degrees and 30 degrees. Yes, my first two pairs are already built, but I have some more puttying and sanding to do before I put the finish on the unfinished portions of the cabinets...before the upcoming weekend, both of the first two pairs should be finished...and hopefully I will have some pics to post shortly afterwards. They are looking pretty nice! Quote Link to comment Share on other sites More sharing options...
Tom Mobley Posted November 18, 2002 Share Posted November 18, 2002 Andy, the finish was really nasty old yellowed varnish, the WAF was was in the toilet. I decided to completely refinish them. Also, while I was installing the woofers I discovered the guy had left out the little wing pieces altogether. So I made a decision to pull the backs and put them in, this also makes it easier to refinish the boxes. The backs were glued and screwed on, it was non-trivial process to remove them without really tearing things up. 60 and 30 is right, my neighbor across the street has an old but very nice Craftsman belt drive table saw, he helped me make them. I made them from the same 3/4" oak plywood I made the front panels from, they're OK. I got tired of screwing around with old finish today, sanding it off with 120 on a DA air sander was just too slow, went over to HD and rented a belt sander, 4x24 belt, heavy thing. Used 120 belt, blew off the old finish from the tops, sides, backs and bottoms in a couple hours. Wood-eatin' S-O-B, that thing is. Gotta be real careful with using it. After the massacre was over I used the air DA again with 320, they tuned out pretty slick. I didn't like how dark they got with two coats of the Tung oil or two of the clear satin poly, so I tried some of that conditioner stuff. seems to help some, and the grain patterns didn't get nearly so dark, I'll probably use it and Tung oil. Tung oil doesn't call for sanding between coats. Tom Quote Link to comment Share on other sites More sharing options...
HDBRbuilder Posted November 19, 2002 Share Posted November 19, 2002 Tom, Don't forget about the splitter piece, if he left that out too!! It is the triangular cross-sectioned piece that attaches to the back between the wing assemblies' apexes. Quote Link to comment Share on other sites More sharing options...
Tom Mobley Posted November 19, 2002 Share Posted November 19, 2002 It's there. It's bigger than the Isophon plans show. I'm thinking there's going to be a clearance issue when it goes back together, there might need to be an "adjustment". Tom Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.