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Smooth Finish On Balsa
13 replies to this topic
Posted 23 April 2011 - 12:26 PM
I have been trying to find information on proper technique for sanding balsa in the UT forums and online. My problem is I keep getting minor depressions between the grains of the balsa after sanding. my understanding is wood has softer and harder grains, so as you sand the softer grains will sander out first. It seems no matter how hard I try I can not creat a perfectly smooth bait. I have tried different sealers to prevent this including, 30 minute D2T, 5 minute D2T, polyurethane, and even a thick paint.
My current procedure is shaping and sanding the bait with 400 grit sandpaper. I then coat the bait with polyurethane and let dry. This causes the wood to lift some producing a rough surface. I sand again quickly with 220 grit followed by 400 grit. I coat again, and sand with the 400 grit. I finish with an extremely thin coat applied with a Q-tip. The bait feels and looks perfectly smooth, but as soom as I put a white base coat, the depressions along some of the grains stand out. I have tried using thick base coats of paint and re-sanding. This seems to work but is very time consuming.
I assume there is either a better way, or I simply need more practise. All the baits i am currently making have flat sides, and I use a sanding block to aid in sanding. The grain run the length of the lure. I use hard balsa wood and basswood. I find the balsa is more prone to this problem than the basswoood.
Posted 23 April 2011 - 12:37 PM
Whatever you use has to be thick enough to cover and have good leveling properties. The smoothest I get is brushing on 2 coats of D2T thinned slightly with a little denatured alcohol, sanded with 400 grit between the coats. Epoxy levels out over grain problems better than most products and is thick enough to fill them in. I've also gotten good results with 8-10 dips into prop (cellulose propionate) dissolved in acetone. Polyurethane I've tried is just too thin.
Posted 23 April 2011 - 12:41 PM
When sanding balsa, sand across the grain. If you sand along the grain, you are just going to remove the soft tissue between the grains.
Forget about achieving a smooth finish before applying the sealer. In fact, the rougher the surface, the better. The sealer has to be thin, to soak into the surface. It will raise the grain, but it will also fix it. Once the seal coat has hardened, then you can go for your finish. expect to do the seal coat thing twice.
Straight D2T is a bit thick for this job. It won't soak in, but if you thin it with a few drops of denatured alcohol, you will get better results. I don't use D2T, but if you do a search on 'denatured' I am sure you will find a ton of information. Personally, I have been using CA glue of late, but I would imagine that on an absorbant material like balsa, this would get expensive, but it does seal well. Propionate would be a good solution for sealing balsa, but lots of members use thinned D2T, so it must work well.
I read your post and it seems that you already understand the problem and your method is on the right track. Get the seal coat right and your lures will shine.
Posted 23 April 2011 - 11:29 PM
I sand my baits with 120 grit, seal with CA glue and a coat of epoxy. Once in awhile I have to sand the baits following the CA glue but not very often. I like flex coat's rod builder's epoxy because it's thinner than D2T to start.
Posted 24 April 2011 - 07:23 AM
I agree with Vodkaman about sanding cross grain. Fine line scratches can be eliminated with the sealer and paint coats. Musky Glenn
Posted 24 April 2011 - 09:24 AM
What benton B said !!!! only diff is i coat whith CA twice sanding between coats
Posted 25 April 2011 - 06:57 PM
Well, I have tried a couple of baits with D2T thinned with a little denatured alcohol without doing a fine sanding. I thinned it less than I have in the past.
I also did a couple baits with thinned E-Tech because I am fining it very difficult to get D2T here in the city, and it is well overpriced. Actually I cannot find any 30 min. epoxies here, except for at a single Ace Hardware. Unfortunatly the dry time for E-Tech is far from desirable.
I guess it's time I put an order in for some D2T at eHobbies. The s/h costs for nearly every material used in making lures is really driving up the costs of building baits, especially cause it seems I am purchasing very few materials from the same location. Oh well, like many have said, we don't build our own lures to save money. =)
Thanks for the help everyone. I will know this weekend if this solves my problems.
Posted 25 April 2011 - 07:55 PM
I don't have an ACE Hardware nearby but many guys say they buy or order Devcon Two Ton epoxy through them. As far as brand goes, I'm doubtful that one brand of clear 30 minute epoxy would be much different than another when used as an undercoating. A number of guys prefer "rod guide epoxy" like Flexcoat. On a per volume basis, it is probably a little more expensive than Devcon. Like Etex, it contains some solvent, but maybe not quite as much. I buy Devcon from www.texaswoodcarvers.com in an 8 oz set.
I understand guys get impatient waiting for epoxy to cure. But the stuff is so good to use in bait making that a little patience will pay dividends.
Posted 26 April 2011 - 08:33 AM
If cost and drying time are issues, get some propionate, as Bob suggested. It's really just plastic that you dissolve in acetone. Solo cups work fine. Mix up a batch in a big glass jar with a metal lid that has a rubber gasket, and it will last a long time. I use either salsa jars, relish jars, or pickle jars, and they work fine. Their lids and gaskets hold up to acetone.
The upside is it's cheap, and you can dip a bait multiple times quickly, because the acetone solvent flashes off fast.
There used to be a guy here, Palmetto, who sold propionate pellets, but I don't know if he still does.
You should be able to google it, and find a source.
Once you get a batch ready, it'll last you a long time, and you can add a little acetone and pellets, or cups, from time to time, to keep it full and ready for dipping.
Posted 26 April 2011 - 06:59 PM
I have heard of using Solo cups and acetone for dipping and was curious about it. I saw a YouTube video of it once. My wife and I bought a bunch of large solo cups a year ago, still have 9/10 of the bag. Does it matter if they are colored (red). I have been thinking of giving this a try. Acetone is readily available. There is a home depot 5 blocks from my work.
I did order 2 9oz sets of D2T. If all I use it for is coating lure bodies, it will last a very long time. I would like to try the solo cups though, as a comparison.
What are the down sides of this method?
Posted 26 April 2011 - 07:27 PM
Did a search on "solo cups" and found plenty of information. Once again, should have done this befor posting the question, sorry. Anyways, looks like a lot of mixed results with the cups. I think I will stay with the D2T and keep trying till I get it right. =) Happy building everyone!!
Posted 26 April 2011 - 07:29 PM
The red cups will color your dip coating a shade of red or very light pink, but for a seal coat, this will not be an issue.
The biggest problem is fumes. Please do yourself a favor and do what ever you must do to avoid breathing these fumes, be it a mask, a fan, ventilator, extractor or work outside.
Another issue with this method is called blushing, but again, not an issue for seal coating. This appears as a dulling of the surface and is caused by humidity. If you want a clear glass like finish, then you need to reduce humidity, but for seal coating, forget about it.
By all means, try the plastic cups. But if you like the results, it will be even better with the propionate pellets and a lot more convenient. I have a mix in a jar, that is over a year old and it is still good to go. It will thicken up some, but all I have to do is thin it down with acetone or what ever thinning agent you use, and you are good to go.
Posted 27 April 2011 - 01:08 AM
I haven't seen Palmetto Balsa post lately, but he's the guy who sells propionate pellets. Shoot him an email.
A couple of suggestions re prop: first, use acetone. It dissolves it faster (about 24 hrs) and flashes off faster when you dip lures into it. You want the solution to be very thin - not as thin as water, but not much thicker. Try a couple of tablespoons in 8-10 oz of acetone and adjust as needed after it dissolves. A thin solution will give you the smoothest finish. If you get it too thick, it will not level out properly and you will get poor results. You can re-dip a lure every few minutes so it doesn't take long to do 5-10 dips.
Posted 30 April 2011 - 09:52 PM
I am still around.
I've just been very busy with life's pleasures for the past year or more.
I still have some of the propionate pellets. You are welcome to message me if you are looking for some.
I hope everyone is doing great, and I do check in every week or so to see who and what is new.