Primitive Archer
Main Discussion Area => Bows => Topic started by: kiltedcelt on January 04, 2010, 01:50:56 pm
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I'm finishing up a couple bamboo backed ipe bows and I applied a first coat of Minwax spar urethane last night around 4:30 PM. This morning at 7:30 it was still tacky to the touch in some areas. My temps in my apartment are not below about 72 - 75F and not humid by any means. This is the first time I've ever used spar urethane. I wanted to get a nice glossy finish but now I'm wondering what I've gotten myself into. How should I go about correcting this problem? I'm thinking if it hasn't dried 10 hours after applying it, it probably isn't GOING to dry. Could I pop the two bows into my heat box and set the temp as low as possible - say 90 degrees for an hour or so and see if that does anything, or go over them with my heat gun on its lowest setting (or a hair dryer)? The finish is tacky in some areas but seems alright on others. However, more of the finish is tacky than isn't. Can a rag soaked in mineral spirits take this stuff off? A guy at the wood working store suggested a chemical stripper but I'm really wary of that and what it'll do to the Smooth-On. I guess I could try sanding it all off but that just seems like the worst possible way to go. If the finish isn't dry by the time I get home from work this evening I'll know for sure that something is wrong. At that point it'll have been on for a full 24 hours or more. These ended up being a couple of really beautiful bows - I don't want to screw them up when they're practically finished. Advice, suggestions? Oh yeah, the urethane sat in a freezing cold car for 4 hours but warmed up to room temperature for 24 hours before I openned the can. Oh yeah, and openning the can - whoo! Something was wrong there because the lid was on so tight I pretty much ruined it getting it off. I finally had to use a pair of pliers to get the lid off and after that it wouldn't go back on tight so I had to place a plastic bag between the lid and the can to make sure it'd stay sealed properly. However, now I'm wondering if the urethane is somehow bad. Maybe I'm better off just stripping the stuff off and putting on Tru-oil or Teak oil or something similar. I ultimately want to get a glossy finish.
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I would think mineral spirits and 0000steel wool should work well to remove the tacky finish. I use Tru-Oil on all my bows and it almost always comes out good.
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I'm with Pat Mineral Spirits should do fine....sounds to me like the Spar was old...or you got it really thick in spots...never had any trouble with the Stuff myself...but then I do most of my Bows with Tru Oil too....but all of my Dining Room Pine is done with Spar ..and it never stayed Sticky at all...so strip it with Spirits and Steel Wool...and use something different next time....even Linseed Oil does fine...JMO
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I know that Ipe is really dense...this will slow the Drying Process down some...but Could you not wipe it down really well with Acetone or some other Degreaser first...then seal it? I have used Carb Cleaner on Osage before that was really oily...and it worked great.....JMO
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On what IPE/bamboo I have done, I used spray Lacquer and could spray another coat aftrer about 2 hours. Worked great
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I have built 4 or 5 ipe bows, after the final sanding I "tack rag" it with a rag wet down with acetone, then use liquid lacquer and rub it in with a rag wet with acetone.....filled the pores real well and of course it dries quickly as well.....you should be able to use any finish over the lacquer.
half eye ;)
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I think the advice you've gotten so far is right on the money, the urethane must have been really old. Was there a lot of separation, requiring mixing, before you used the stuff? Steel wool and mineral spirits should do the trick. I would avoid chemical strippers, they tend to have xylene and other such things in them, and can rip through a lot more than just paint. The acetone should work well for degreasing. For a nice glossy finish, I have used the following method with some success on hickory.
1st step: Apply linseed oil, rubbed in, and set with a heat gun, can be followed by a second coat, for paranoia's sake, again, set with the heat gun. This is to waterproof the bow. I know this sounds weird for an oily wood like ipe, but liseed oil sets to a varnish, with heat. I would bet the spray laquer might work even better, as I said befor, this was a prep I used on hickory
2nd step: Degrease thoroughly with denatured alchohol. I wouldn't use acetone, as you want some of the linseed oil to stay put, not to strip it right back out of the pores. You could skip this entirely if you used the spray laquer.
3rd step: Apply clear, water-based polyurethane, explaining the need to waterproof, then degrease the bow. Apply 5-6 thin coats, sanding lightly between coats, making sure to sand out drips and brush marks. Let it dry hard, before applying subsequent coats; you don't want to risk sealing in moisture, even with the linseed oil base. The reason for water-based is that it dries clear, not yellow, dries faster, and dries harder than oil based poly.
need to split the post. BRB
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for some reason, the browser wont let me stay scrolled down, to see what i'm typing, so I had to split it.
4th step: Sand lightly, with successively finer grit, say 100-150-220-300-etc. Don't take off too much of the finish, just take out the brush marks, and finish sand. Sand with linseed oil as a lubricant , when you get to 300 grit and finer. You can finish with steel wool, but I usually just go with 600 grit paper. Hand rub it with linseed oil, and let it dry. It will look like glass when you are through.
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I don't know about spar urethane, but I can tell you from recent experience that Tru-Oil will not dry properly when applied directly to ipe. When you do get the urethane off, seal the bow with shellac and then put whatever finish you like over that.
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You have to be patient with it. It's good stuff. It's truly an exterior finish and worth the wait for it to dry. Put it near a heat source. Jawge
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Gordon, I've not had any problems applying Tru-oil directly over Ipe. On a couple of the bows where I used edge grain wood I used super glue to help fill in the wood's pores. But that was just on the belly of the limbs. Then applied Tru-oil over that and the rest of the bow. I think I just used mineral spirits to clean the wood with before appling the finish. First coat does take a little longer to dry though. ART
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Art,
I've only applied Tru-Oil directly to ipe only once (recently) and it did not work well at all. It could have been an anomoloy, but I will continue my normal practice of applying shellac as a sealer in any case - it's good prevention for a variety of potential finish issues.
Gordon
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It's not the varnish, it's the ipe. I have had absolutely no luck getting any finish to stick to ipe until David Knight told me to use lacquer sanding sealer before putting the finish on. Works great. The spar urethane is a really good finish, and will stick to about anything except ipe. Once you get the sealer on, though, it works fine.
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Well if anyone would know it would be David Knight and James Parker... ;)
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Been there done that. Frustrating but the best thing is to remove the finish with acetone and seal it with spray shellac then whatever over that. Make sure its the wax free spray because some shellac has wax and thats not what you want. Never tried the sanding sealer. I talked to one of the tech guys about it and he said it has wax in it as well for sanding and is not a good choice but if it works for David it must work. I will never put another oil base directly on ipe. My favorite is water based spar because it dries fast and is tougher than oil base finish. Problem is that its only brush on and only one company I know of makes it. Hope this helps.
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Thanks for all the replies guys. I talked to the seasoned older guy that runs the park district wood shop I occasionally go to and he suggested the same thing as Jawge - let it sit and dry. He had no doubt that it would finally dry but that as cold as it is right now it might take several days to dry. I live in an apartment with steam heat that alternately comes on and makes things occasionally uncomfortably warm followed by turning off until it gets uncomfortably cool. So, I've got temperature swings working against me as well. My buddy the shop supervisor said he thought as long as I had thoroughly sanded the ipe before applying the finish I shouldn't have any problems. Also I brushed it on as per the instructions and it was probably a bit thick. For future reference, he suggested applying it with a rag so that it would go on in a very thin coat that would dry much more quickly and could be easily worked in a much shorter time frame. I'll let it sit for a couple more days and see if it's getting any better over time. It's already dried on the bamboo back, but I think I had to apply more finish to the ipe because it seemed to be a good bit more absorbent than the bamboo, so I'm sure I applied it far thicker on the belly than anywhere else.
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Well this is now I think about day three and the finish was dry everywhere but the ipe. So, I used a scraper to take all of the finish off of the ipe and I'm going to go back in and touch up some boo-boos that should've been sanded out that I missed. I'll degrease with denatured alcohol before applying any finish. I have some Deft sanding sealer and Deft lacquer - both are brush-on. Do you guys think this will work? The Deft lacquer gave a nice really glossy finish on the one bow I used it on. I just haven't used it since because it incredibly smelly stuff.
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Oh yeah, one more thing. I don't want any more mess ups this time around. I'm going to clean it with denatured alcohol before applying the finish and if you guys have any suggestions for the best way to apply a foolproof glossy finish I'd appreciate it. Please specify brand names if you can. I plan on sanding tonight and tomorrow after work I can go and get whatever finishing products I need based on your suggestions - that's assuming that there's something better than the two Deft products I already have (sanding sealer and lacquer).
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I'll tell you what you don't want to do unless you want another mess. Donot apply Lacquer and then Tru oil. You will have a gummy mess.
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I'm surprised to hear of all the problems with tru-oil on ipe. I just finished putting the 5th coat of tru-oil on my 4th bow that I have completed from one of David's blanks and I've not had any problems. I clean it really well with a rag wetted with acetone and it works well for me. I have had a problem getting it to stick to cocobolo which is very oily, so I seal it with superglue gel first and then go with the tru-oil after that.
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Been tellin Em to use Acetone !....it aint going to hurt no Glue Up....unless you soak it in a Tub of it......... :P
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It's not the varnish, it's the ipe. I have had absolutely no luck getting any finish to stick to ipe until David Knight told me to use lacquer sanding sealer before putting the finish on. Works great. The spar urethane is a really good finish, and will stick to about anything except ipe. Once you get the sealer on, though, it works fine.
LAQUER SANDING SEALER? where do you get this stuff?
I agree with Gordon taht Shellac is great stuff to seal the wood. I just gotta form the habit of using it on every bow I think.
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It's not the varnish, it's the ipe. I have had absolutely no luck getting any finish to stick to ipe until David Knight told me to use lacquer sanding sealer before putting the finish on. Works great. The spar urethane is a really good finish, and will stick to about anything except ipe. Once you get the sealer on, though, it works fine.
LAQUER SANDING SEALER? where do you get this stuff?
I agree with Gordon taht Shellac is great stuff to seal the wood. I just gotta form the habit of using it on every bow I think.
I've bought it at Lowe's before. Works great and dries fast. Just make sure and get the Deft. I tried a bargain brand and all it did was clog, world of difference in quality but not much difference in price.