SMO

SMO

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I will soon be trying my hand at building some fuel tanks for my -4. This was originally built in 1987, so I could not use the prepunched kit, but had to get the non-prepunched kit. I found some good threads on methods, and still have a couple questions for the many who have traveled this path before me.

How many hours should I expect to need to build the tanks? I have a reasonable amount of experience with drilling/deburring/dimpling/riveting but none with Proseal.

For those who have used a Semco gun (any excuse to buy a new tool) for dispensing the sealant, what model do you recommend?
 
I am currently elbow deep in proseal for my tanks. It takes quite a while as there are lots of little parts and stuff and then there's the proseal. I think you could knock them out in a month or less if you really dove in.

Overall the proseal is not too bad. There's a bit of a learning curve but just make a mess once or twice and you'll start to get the hang of it.

One thing I recommend is to use a paper funnel thing. Instructions on how to make it:http://www.youtube.com/watch?v=lHHv22G8ixo. I just used paper out of my printer and then taped around the seam and the tip for reinforcement. It was very clean and made beautiful fillets and was perfect for controlling the proseal.

Here's a link to my site: http://www.rv8plane.com/wings/18sep11.php. About the last 15 updates have been me working on my tanks and the time I've spent for my 8, feel free to take a look.
 
Model 250

Semco Sealant Gun Model 250. I think there is an -A and -B suffix depending on the trigger style. I like the paddle switch pictured below rather than the handle style. I have both and this is easier to control and get into tight spaces. I'll deny it if questioned but the Semco made it almost easy. Nozzles and cartridges came from Brown Tools. http://www.browntool.com/Default.aspx?tabid=255&txtSearch=semco&List=1&SortField=ProductName,ProductNumber. Liked the 2.5" with 1/8" tip best. Semco was from the big auction site. Be sure it comes with the factory hose.

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Semco size

Thanks Larry, is yours the 4 ounce or the 2.5 ounce gun?
Did you find you had enough capacity or would you buy bigger next time? I see there are 6 and 12 ounce units as well in the 250 model.
Do you change cartridges and tips each session or is it easy to clean these out?
 
I wrote up my tank building experience in another thread. I did both tanks in about 2 months, with some time off in between.

I had really great results with just using the canned sealant from Van's, mixing it on a paper plate with a cheap Harbor Freight digital scale, and using a veterinary syringe as an applicator. The syringes were $2 and are disposable. Using the syringe to lay down a bead of sealant, then using a plastic picnic knife as a spreader was perfect for all of the surfaces that needed sealing.
 
I'm with Bruce on this one. If money is important to you, there's no need to spend money on a tool that you'll only use once. I obtained some syringes (minus the needles) and used them like he did, with excellent results. I also highly recommend the faye sealing method. I tried it both ways.

These syringes work great for applying a bead of sealant to each rib. It's like a mini caulking gun. A pharmacist at Target was kind enough to give me a few of these for free (!!!) when I explained what I needed them for, and emphasized that I didn't want or need the needles... just the syringes. You should have seen him smile. I was even able to clean them up with MEK so they can be used again.

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Mark,

I have both the 2.5 oz and the 6oz. If I could only get one, it would be the 6oz. The tubes and tips were cheap so I got 4 of each. The proseal pops right out after letting it dry overnight even on the tips. Just be sure and pull the little rubber plunger out of the tube before letting it dry, though. Learned that one the hard way.

I tried syringes but didn't care for them. YMMV. One thing I really liked was being able to dot the dimples when wet setting rivets. The gun stops immediately when you let up on the paddle or trigger so you can get the amount just right. I use Rick G's method of fay sealing. He has a good write up on this forum about how to do it.

I wasn't in a rush to buy and ended up getting a complete setup for under $30 shipped. My Tech Counselor (3 time RV builder) liked it so much that I bought him one as thanks for all his help. He's using it on his RV-10 tanks right now.
 
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