Dave Welch's Kilo WTC

[anonymous]

Thought I'd post my progress with Dave's very well made WTC for the Kilo.

My home built was working well but being new to all this I didn't know the acrylic would be a problem. Pressure caused it to crack and leak. Live and learn.

So I ordered one of Dave's WTC's and it's just great. Dave has also been very helpful too with my questions always answering my email and giving the best answers.

Everything works the way he shows you in the CD that comes with the WTC. You can't beat the deal he offers.

I'll continue to show up dates and video of the boat in action.

Just waiting for the smart products pump to show up and the rest will be done quickly. I'm using the same pump, motor and bladder as Dave. His CD tells you where to get all the items you need. I got the Maxon motors from Dave as well.

Steve









Edited By U812 on 1107246596

[Guest]

You had Acrylic tubing crack

You had Acrylic tubing crack on you?!!

I've used acrylic for years in my subs, without any problems at all.

They use it for the full size boats too, as Acrylic is more rigid.

Maybe you had a bad batch?

The extruded acrylic tubing does have lots of stresses in it.

In the UK, if you want clear tubing, then it's almost obligitory to use Acrylic, as polycarbonate or lexan tubing is in the unobtanium category.

I'm sure OTW use acrylic for their WTC's, no failures reported yet.

Andy

[tmsmalley]

A lot of the cracking

A lot of the cracking in acrylic I have experienced was due, not to water pressure, but my use of the incorrect type of silicone RTV (Room Temperature Vulcanizing) adhesive.

The gas some brands release during the curing process (Shoe Goo and other "Goo" products especially) can cause plastic materials (Lexan too) to "craze" and crack.

I now throughly test whatever brand of adhesive I am using on a piece of scrap before using it on WTC tubing. It seems to me (I may be way off here) that the more STRONGLY a silicone RTV smells of acetic acid as it cures, the more probable it is that it's going to crack the tubing.

I have switched to the clear "Permatex" brand from the local auto parts store and have had no more problems.



Edited By TMSmalley on 1107293378

[anonymous]

Andy and Tim,

Thanks for the

Andy and Tim,

Thanks for the input on this subject. I wondered about the silicon as a possible cause. It did have a stringent smell to it. It was Devcon. I'll get some Permatex. Good tip Tim and I appreciate it.

My home built WTC looked like a shattered wind shield. I just got up one morning and there is was.

I used a bands to cut it. I understand if your not care with the cut this can result in the same effect. With the o-rings creating pressure from the inside out even the smallest fracture will grow and grow.

Still I will stick with lexan as we can get it just about everywhere in the US.

And Tim. Your right and little dab of the material you plan to use on the product as a test is always the best way.

Steve

[tennesseejim]

While we are on the

[color=#000000]While we are on the topic of acrylic tubing - what is the best bandsaw blade to use to cut it? I have two blades for my work bench band saw]

[collins class]

Steve

How did you mount your

Steve

How did you mount your motor in the rear compartment? Did you use the same faceplate setup as Dave did?

Which seals did you end up using?

Cheers

Byron

[anonymous]

Byron,

I used subtec seals but

Byron,

I used subtec seals but I replaced the o-rings with hardware store type. 1/4 OD 1/8 ID. Dave tells you to do this in the instructions. The Subtec seals can't handle the vacuum but the hardware seals do.

The engine is mounted exactly the same as Dave's. I followed his pictures to the letter.

Jim,

I have a fine blade on my bandsaw but it's been on there so long that I can't remember the exact type. It cut easy enough. The first WTC I made was for the type 7 and it's holding up fine but the one for the Kilo looked like a broken wind shield. If you can go with the Lexan do it. Dave will back me up on that.

Steve

[bigdave]

I have had terrible luck

I have had terrible luck with acrylic tubing. I do not believe the cracking is due to pressure but the cutting and drilling of the plastic. It is very hard to make a good cut or hole in it. It is I believe a harder more brittle material than the Lexan. The Lexan absorbs the shock of the cutting just like it gives when it takes a bullet. I have found even if you think you have a good cut if you lets say cut off a section on a band saw. Try to clean off the end of the tube with alcohol and presto, it will show the minute cracks that are there you just could not see.
Tim is correct about the Goop, as much as I love using Goop it will seep into minute cracks and it’s spider web city. It has toluene in it. I use a good marine or aquarium grade of RTV. I have to admit I do still use the Marine Goop on Lexan sometimes, as it is not as prone to cracking. This is just my opinion. Dave.

[Guest]

Acrylic is more brittle than

Acrylic is more brittle than Lexan.

I've worked with lexan sheet, and it is almost waxey in texture.

This means it will deform easier under pressure, but I don't think this is an issue for models.

I find a little soap mixed with water is valuable when cutting or turning acrylic, also use a fine(ish) blade and cut slow.

I don't use silcone sealant, I prefer to use o-rings and compress them against the end of the tube, as opposed to fitting them inside.

This is because I've found that the inside of extruded acrylic tubing isn't very round.

Future models will use ABS or stainless steel tubing. I think the virtues of a clear WTC are a bit overstated, although they do look pretty.

Andy

[bigdave]

When I use RTV I

When I use RTV I only use it as an adhesive not a sealant. If something has to be attached to the tube. The soapy water is a good idea, I will have to try that.

[anonymous]

Well except for a little

Well except for a little wiring she's done. Can't believe how much stuff you can get into this little WTC. Even a full sized RX.

Steve

[anonymous]

Here's a picture of the

Here's a picture of the WTC in the boat. This WTC fits perfectly!

Steve





Edited By U812 on 1108108615

[anonymous]

Tested the WTC today. First

Tested the WTC today. First just the WTC to see if there were any leaks. None. Not a drop.

Then tested the RCABS and controls and prop shaft. Not a drop. Not even any fogging inside the WTC.

Then I placed it in the boat. Trimmed it and tested again the RCABS and controls. Still nothing. Let it sit in the tub for a good long while submerged. Still not a drop.

Only thing holding me back now is the SC-10 for the boat. I'm running the Maxon motor which requires at least 11.1 volts to run at a decent speed. They are back ordered as are the Subtec ST-10. I've ordered both and will see what one gets here first.

Once I get the ESC I can then use the 11.1 volt lipo pack and I'll take video to post.

I'm very pleased with Dave's workmanship and readiness to answer all of my dumb questions. He was great.

If your considering getting one of these little WTC's I wouldn't hesitate a bit if I were you. It works hands down and I couldn't be more pleased.

What a kick it was to watch the sub rise up and down again without ever having to move forward. Pure magic.

Steve



Edited By U812 on 1108284249

[turbobearcat]

Steve

you should try that 8

Steve

you should try that 8 bladed prop I got for mine, I think you will like what you see


Mark

[toypilot]

Turbobearcat , where did you

Turbobearcat , where did you get your prop at?

I am also working on one of these kits and just ordered a Mtroniks Sonik4 RV Max w/Reverse 8T ESC, hope it works well with this setup. This I bought from Hobby People.

I also have coming a Futaba "4WD" radio, I liked it because it has the small receiver. Bought this from Tower Hobbies.

Dave Werkema