KenVW

Hello,
I am building a Kyosho Stearman PT-17 ARF. I am at the point where I assemble/detail the dummy radial engine. I have trimmed both halves out of the sheets per the instructions & they are now to be glued together. I took a couple of the scrap pcs of this plastic & did a test on them with medium CA. They seemed to snap apart. I then thought of my model car days long ago & got a tube of Testor's glue & just did an overnite test. This didn't work either. I expected the testors glue to "weld" the plastic together but this morning I pulled it apart & the glue was still gooey & the plastic was unharmed.

I did the CA test twice, the 2nd time it wasn't quite so bad but I can imagine this popping loose while the Saito is running.Not good.

What should I be using? The instructions don't say what to use or what kind of plastic it is. It is smooth, white, & shiny. rather brittle, while the cowl is definately fiberglass. I was thinking of 6 min epoxy??

Thanks,
Ken

rwright142

I don't know what your dummy radial is made out of, but of it's styrene I'm using it for my [link=http://www.rcuniverse.com/forum/m_4982309/mpage_8/key_/tm.htm]Corsair Cockpit[/link]. I bought it and a clear bottle of adhesive at my LHS. They have a display case and the products are made by Plastruct. The adhesive I use is called Bondene. Here's a description:

BONDENE CEMENT
Bonds instantly. Sets in seconds - bonds permanently in minutes. Economical to use. Special formulation dissolves a thin layer of each surface to be joined. It evaporates quickly and forms a welded joint; one as strong as the surrounding plastic. Apply with a small brush or blunted syringe-type applicator. Capillary action will spread it the length and breadth of the joint for a continuous solid weld. Bondene works on all "alike" Styrene, Butyrate, ABS, Acrylic and Copolyester applications.

bkdavy

My Feedback: (1)

Its probably ABS plastic. Depending on how much you have left from cutting the pieces out, one technique that works for me is to dissolve the scraps in acetone to make a thick mixture. I then put this on the seam, and then put the seam together and tape it (masking tape works OK). The acetone in the "goo" will weld the joint together. give it a day or two to fully evaporate away, then sand the joint smooth.

Brad

KenVW

thanks guys, all input is appreciated. I will check our LHS for the glue, sounds like it should work.

Brad, I do have all of the scrap from cutting both halves of the radial out of the sheets, which BTW is a tedious job for one who struggles with patience . I have acetone and will try to make this "goo" you speak of tonite.

Steve Collins

My Feedback: (8)

Get yourself a tube of E6000 at a craft supply store or hardware store. Great stuff with a super strong bond. The plastic you described is ABS. E6000 work especially well on plastics and is also one of the best glues for canopies as well.

Innovative Model Products sells the same stuff repackaged and called PFM.

Deadeye

I hope you used some of the scrap ABS as tabs, meaning little strips inside the piece on the seam. If you use that method, scuff up the inside with 80 grit, thin CA should wick in and bond the pieces no problem. I always lay up 3/4 oz minimum FG cloth in the seam afterwards, and either ca that in or epoxy it in.

Dr1Driver

If it's styrene, get a bottle of Tenax, available at your LHS.

Dr.1

Charlie P.

Once you have it "butt-spliced" together you can also epoxy a 1/2" strip of light fiberglass (or coffee filter paper) to the backside to reenforce the seam.

KenVW

OK, now I'm confused.

The little tabs...butt splice.

I did read on a website that sold dummy radials to lay engine half on a sheet of sandpaper & sand till its ready to break off.
Do this to both halves & your set for a butt splice.
I was afraid of this method because it's not their brand of motor & I am not confident that the two molds are identical enough to do that and line up.
also... the instructions do say (or I read it somewhere) to cut around each cylinder leaving a small flat to apply glue to. This is what I've done. I sawed them out on a scroll saw leaving approx 1/8" or less & tried to be uniform. After gluing both halves together, I was planning on taking a dremmel & "evening/smoothing" up the glued joint.
Then Paint & detail

I realize this will leave a little flat tab down the centerline but should be strong & not too noticable once painted.

Is this a bad plan? I've never done one of these before.
Ken

Note: I am dealing with 2 halves of a dummy radial, attaching to make a completely exposed engine, not inside a cowl where I would be gluing to the cowl only. getting to the backside of the seams would mean getting on the inside of each cylinder, I don't think thats doable.

KenVW

Worked out in the garage tonite on the stearman. I did find some glue I had here that I think is going to work fine. I put in a tile shower recenly & have a can of Oatey glue for the vinyl shower pan under the tile. I put a test pc together & it looks like its really bonding/welding together. I will check it tommorrow.

Charlie P.

By "butt splice" I meant just where two pieces contact along a narrow seam (no overlap). Once you have that cemented I meant you should reenforce the inside (assuming you can get in through some opening??) with epoxied strips.

KenVW

Charlie,
I understand now...lets just say I had a senior moment. My plan is to leave a small flange on each half (per the plans) and glue them together. I do have limited access to the inside of the joints thru the center hole on the back half. The joints are not flat, straight, or parallel with each other, its all "curvy" or shaped so getting a small pc for a joiner will be difficult. I could however mix epoxy & get it to run down the joint on the inside. I also read of one guy who built this same plane & filled his dummy engine with the spray foam insulation to give it some solidity w/o weight. my luck would be it would expand & blow the 2 halves apart again.

got the cowl cut last nite, servos/rods installed. this motor is going to be my holdup...but hopefully it will look awesome once finished.


here is a [link=http://www.geocities.com/jbrundt2/N2S-1.html]LINK[/link] to another guys plane. I was so impressed with this, I am doing mine exactly the same. I emailed him but got no response. there are good photos of his build including the finished radial/cowl.

Ken

KenVW

Well, I finally found a glue that seems to work great. I ended up using general purpose Oatey Cement for PVC, ABS, CPVC in the red can. worked on a test pc so I applied with QTips to both halves of the radial & lightly clamped together. Once glue dried I match trimmed the joint with a dremel, sanded then Q-Tipped more glue inside each cylinder at the joint.

I then after trimming away the one cylinder where my saito will be and tried to pull it apart. It seems to really be bonded together well. On to the painting.

thanks for all the input
Ken