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Howitzer build - Page 8

post #211 of 452
9/5/11 at 12:46pm
Thread Starter 
Man, your car looks great, LooneyBomber!
I need you to demonstrate your technique on my truck.
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post #212 of 452
9/5/11 at 1:29pm
Ah, I just remembered that I forgot to get the discount code and the sale ends tonight. I can get it when I get home from work, but it won't leave much time for ordering.

PI, thanks for the compliment, but if you do to your truck what you did for your NHT build, you will get the finish you desire. No need for me to demonstrate...unless it comes with complimentary beverages.

From my email.
Quote:


Pre-Labor Day Special

Okay you asked for it and now you got it.

20% off your shopping cart at Detailer's Domain

Starts Now
Ends on 9/1/2011

Please use PROMO CODE: LABOR

...Whoops.
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post #213 of 452
9/6/11 at 9:47am
Thread Starter 
I missed that sale, but there should be others coming up before long.

Here's a follow up on the Harbor Freight gun.
The finish looks fine on the small stand. No complaints. (I will add some drawers to that stand later, that's why I left it open).




There is a little bit of rust where you screw the cup onto the gun, so it seems reasonable that there is rusting elsewhere inside the gun. You need to clean any gun every day anyway. Just use your air hose to blow the water out of this gun after cleaning and you should not have to worry about rusting.



Howitzer progress should resume later today.
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post #214 of 452
9/8/11 at 8:24am
Thread Starter 
I decided to remove the veneer from the baffles and reuse them, rather than send them to the landfill.

I didn't take any pictures, but a heat gun loosened the adhesive and I scraped the veneer off very easily.

Then came the adhesive removal. Let's just say it would not be hard for me to imagine a more enjoyable activity. On one baffle, I poured on some Acetone and used a carbide scraper for most of it, then sanded the rest off. On the second baffle, I just sanded only. Neither one made my Top Ten Fun Activities list.

The Vacuum Veneer Press build is here.
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post #215 of 452
9/17/11 at 8:21am
PI,

I noticed you used some contact cement that John had mentioned in another thread. the 3M Fastbond stuff. I probably live pretty close to you and was curious if you were able to find some of this stuff locally or did you have to order it online?
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post #216 of 452
9/17/11 at 1:12pm
Thread Starter 
Nate--I got the Fastbond off Ebay. I have some you can try if you'd like. PM me.
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post #217 of 452
9/18/11 at 8:50am
Thread Starter 
I decided to re-do the veneer on the top edges of the two front baffles.
Clamping seemed the best way.

Yeah, it might be clamping overkill, but I hate veneer bubbles.



Non-stick aluminum foil between the caul and the workpiece prevents the caul from sticking to the freshly glued veneer. I used some 5-minute epoxy for this part.
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post #218 of 452
9/18/11 at 3:27pm
Quote:
Originally Posted by PassingInterest View Post

Yeah, it might be clamping overkill, but I hate veneer bubbles.

'Clamping overkill'? What's that?



Just wanted to throw out a quick 'thank you' PI, your documentation of this build helped get me off my buttocks and start on my next project (as seen above).
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post #219 of 452
9/18/11 at 4:20pm
Thread Starter 
Nice clamping, Chris.
Those Quick-Grip clamps are great.
But, where's your build thread link? Quit holding out on us.
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post #220 of 452
9/19/11 at 12:33pm
Quote:
Originally Posted by PassingInterest View Post

Nice clamping, Chris.
Those Quick-Grip clamps are great.
But, where's your build thread link? Quit holding out on us.

I am building the TM version of Curt's AviaTrix. I have a build thread for the MTM version from last year over at HTGuide, but they just didn't look right when I was finished with them.

I am thinking of starting a new thread for the TMs over here at AVS. I am trying a few new things this time, it should be interesting to see how they work out. The new thread should be up by this weekend.
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post #221 of 452
9/19/11 at 12:38pm
Thread Starter 
Tip: For a really clean cut with a veneer saw, a 2 inch thick straight edge will help you keep your saw perfectly straight.




Veneer Stitching.






Spread some glue on the substrate.




Vacuum press the veneer on the baffle.



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post #222 of 452
9/19/11 at 1:57pm
Thread Starter 
Chris, I remember your MTM build. I look forward to your TM build.

This is the second baffle and it has been in the vacuum press for 2 hours, which should be long enough.




Let's take a closer look at that gauge.




That's enough pressure to crush a mold if I were using one.
I forgot to time it, but I think I got to pressure in about a half minute, not counting pre-charging the tanks in advance. The pre-charge takes about 10-11 seconds.

Edit: I should mention that I use plastic on my gauges, held in place with rubber bands, to avoid clouding the gauge with overspray.
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post #223 of 452
9/19/11 at 2:25pm
Thread Starter 
Using the vacuum press made this task very easy.

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post #224 of 452
9/19/11 at 2:26pm
That's the prettiest picture of a pressure gauge I've ever seen
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post #225 of 452
9/19/11 at 4:32pm
Thread Starter 
Ain't it though? It got so much pressure, it's off the scale! I was afraid the used/rebuilt pumps might be a little weak, but they're real performers.
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post #226 of 452
9/19/11 at 5:02pm
2.036254 inHg = 1 psi

atmospheric pressure is 14.7 psi.

assuming the impossible, that you were able to pull a complete vacuum (evacuate every single air molecule from inside the bag), you would be at 29.93 inches mercury, which is why the device ends at 30.

the BAR rating is 100xkpa = 100 x kpa = 100 x 1000pa = 100,000pa = 1 atmosphere, so -1 is the point where you would be pulling a full vacuum at sea level, average temp/humidity day. which is why the gauge ends there (there is a minor difference in the two calculations, but don't sweat that).

with these negative pressure devices, all they do is suck out all the air that is combating atmospheric pressure. that allows the atmosphere to "crush" in on the object. however, the maximum crushing power is limited to 1 atmosphere--the pressure at sea level on an average temp/humidity day.

something doesn't add up.

your device is awesome pi, no knocking it.
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post #227 of 452
9/19/11 at 5:21pm
You've come a long way, PI. Just a short 11 months ago...

Quote:
Originally Posted by PassingInterest View Post

Toyota Veneer Press.


Quote:
Originally Posted by PassingInterest View Post

I got tired of fighting the curling veneer, so I switched to contact cement.



LOL!
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post #228 of 452
9/19/11 at 5:38pm
Thread Starter 
LTD02--You know I love it when you talk math! It's like a foreign language, only cooler.
Thanks for letting me know that something is not quite right.

I wonder if the gauge is temperature sensitive. After all, I had wheeled it out into the driveway and into the sunshine to give myself more elbow room in the garage. It's either that or the gauge is just plain dishonest. I will check the vacuum at different times of the day tomorrow, just to see if the reading changes as the day warms.

Edit: Oh yeah, it rained last night, so the humidity was pretty high today. Not sure if that makes much of a difference.
I really appreciate your setting me straight on this. As I said before, I don't know much about vacuum presses.


dykz34--I still like my Toyota Veneer Press. Thanks for remembering. But I have to say that vacuum bagging was so easy, I don't know why I didn't do it sooner.
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post #229 of 452
9/19/11 at 5:46pm
pi, what was the reading on the pressure gauge when you shut the vacuum pumps off?

alas, who cares about the maths, back in #222, that just looks awesome. wish i had you for a neighbor!
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post #230 of 452
9/19/11 at 5:52pm
Thread Starter 
Quote:
Originally Posted by LTD02 View Post

pi, what was the reading on the pressure gauge when you shut the vacuum pumps off?

I snapped the photo you saw, then turned off the pumps. So, it read > 30 Hg.

I think I'll run out to the garage right now and see what I get.
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post #231 of 452
9/19/11 at 6:01pm
Quote:
Originally Posted by PassingInterest View Post

LTD02--You know I love it when you talk math! It's like a foreign language, only cooler.
Thanks for letting me know that something is not quite right.

I wonder if the gauge is temperature sensitive. After all, I had wheeled it out into the driveway and into the sunshine to give myself more elbow room in the garage. It's either that or the gauge is just plain dishonest. I will check the vacuum at different times of the day tomorrow, just to see if the reading changes as the day warms.

Edit: Oh yeah, it rained last night, so the humidity was pretty high today. Not sure if that makes much of a difference.
I really appreciate your setting me straight on this. As I said before, I don't know much about vacuum presses.


dykz34--I still like my Toyota Veneer Press. Thanks for remembering. But I have to say that vacuum bagging was so easy, I don't know why I didn't do it sooner.


While it could be a defective gauge, they are definitely temperature sensitive. You should not be able to pull more than 25 to 26 mm Hg with those pumps (and that is PLENTY!!!).

Awesome setup by the way... I dug my vacuum pump out yesterday evening while cleaning up my mess of a shop. Need to wire it up and see if it will work.
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post #232 of 452
9/19/11 at 6:21pm
Thread Starter 
Just for reference, here is the gauge with no pressure--valve open to the outside world. Photo taken at 8:00 pm Central Time USA. I don't know what the temp is in the garage.



Then I turned it on and let it run for a few minutes and this is what I got just moments ago. The valve is closed, of course. Logically, I should be able to exceed what I had earlier, since I no longer have the valve open to the bag, so there are fewer places for leaks. I think it is a temperature issue.



lilmike--Thanks! I hope your pump still works. And thanks for confirming the temperature issue with the gauge.
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post #233 of 452
9/19/11 at 6:48pm
"Then I turned it on and let it run for a few minutes and this is what I got just moments ago."

that looks better. you are pulling a near full vacuum...props to your build on the vacuum machine! :-) off the top of my head, i have no idea what would produce the previous reading, unless you were in the arctic, below sea level, or under water. :-) the blue sky with some clouds suggests none of the above.

just for fun let's say you are pulling 14psi x 12^2/sq ft = 2016 lbs / sq. ft. = ~1 ton per sq. ft. that is a tremendous force. hopefully...no bubbling.
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post #234 of 452
9/22/11 at 6:04am
Thread Starter 
Quote:
Originally Posted by LTD02 View Post

just for fun let's say you are pulling 14psi x 12^2/sq ft = 2016 lbs / sq. ft. = ~1 ton per sq. ft. that is a tremendous force. hopefully...no bubbling.

Yes! I got good adhesion everywhere. No veneer bubbles!


Trim the veneer overhang.




Both baffles are doing well. I sprayed two coats of DeWaxed Shellac. Then I used the Minwax Oil Modified Water Based Poly for the base coats. I'll use the water based lacquer mentioned earlier in this tread (thanks again, Max) for the top coats. Next, the baffles will get a light scuff sanding/smoothing with P220.

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post #235 of 452
9/23/11 at 10:15am
Thread Starter 
Let's make a template to route the driver recesses.
I've already marked one center.

Tip: If you'd rather avoid dividing fractions because you're in a hurry, just angle the ruler so you land on a whole number at the edge and divide that in half.




I could use any whole number, but for this illustration I used 20".
The vertical center is at 10", even though the board is 16 5/8" wide. Nice and easy.




Driver recess template.




Now let's make an insert ring for routing the driver through hole.




We can use the larger recess template to make through holes on the box.




Secure the template.




Remove some waste. This will make routing easier.



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post #236 of 452
9/23/11 at 1:34pm
Thread Starter 
Lineup on center marks, clamp and route.




Make some sawdust.




Cleanup.




The bucket is nearly half full. This will be the third time emptying the bucket and there's hardly anything in the shop vac at all.




The real benefit of the Dust Deputy is the shop vac's filter stays clean. I would normally have to clean the filter long before the vac needs to be emptied.

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post #237 of 452
9/23/11 at 7:57pm
Thank you for the detailed build thread, I am getting a lot of really good ideas for my next build. The dust deputy looks like a great way to ease cleanup.
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post #238 of 452
9/24/11 at 3:43pm
Thread Starter 
Quote:
Originally Posted by NWCgrad View Post

Thank you for the detailed build thread, I am getting a lot of really good ideas for my next build. The dust deputy looks like a great way to ease cleanup.

You're welcome. I'm glad to help.
The Dust Deputy is worth it if you make a lot of sawdust.
That is, if you have to clean your filter a lot.
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post #239 of 452
9/26/11 at 6:07am
Thread Starter 
Mark the driver screw holes.







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post #240 of 452
9/26/11 at 6:51am
Thread Starter 


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