Another rust question... - Hot Rod Forum : Hotrodders Bulletin Board
Hotrodders.com -- Hot Rod Forum



Register FAQ Search Today's Posts Unanswered Posts Auto Escrow Insurance Auto Loans
Hot Rod Forum : Hotrodders Bulletin Board > Tech Help> Body - Exterior
User Name
Password
lost password?   |   register now

Reply
 
LinkBack Thread Tools
  #1 (permalink)  
Old 04-02-2005, 05:33 PM
S10xGN's Avatar
Gotta love a turbo!
 

Last journal entry: Body on Frame today.
Last photo:
Join Date: Aug 2004
Location: Port Neches, TX
Age: 61
Posts: 1,656
Wiki Edits: 0

Thanks: 0
Thanked 60 Times in 56 Posts
Another rust question...

Well, I spent 3 hours today to get about 3 square feet of my car blasted. Most of this was learning how to use the blaster (I didn't throttle the sand valve and dumped my first 50# sack of media in 5 minutes!) and trying to see through the absolutely CHEESY plastic face shield. I finally got the valve adjusted and things went a little better. I'll need a a better hood for sure! The media (AL-OX) is not dusty at all, but the plastic facepiece is no longer "clear"...

Anyways, please look at the pix and tell me if this finish is OK for (SPI) epoxy primer as is or does it need to be absolutely free of rust. This question strictly applies to the interior surfaces only. The exterior will be spotless.

BTW, I'm using AL-OX 46 grit. It's awesome at removing paint, but still lacking at heavy rust. Went through 200# today and spent 2 hours "recovering" and sifting the spent stuff. It's supposed to be good for 80 or so uses.

Russ
Attached Thumbnails
Click image for larger version

Name:	roof inside.jpg
Views:	118
Size:	61.0 KB
ID:	4517   Click image for larger version

Name:	roof blasted.jpg
Views:	120
Size:	50.3 KB
ID:	4518  

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 04-02-2005, 06:33 PM
MARTINSR's Avatar
Brian Martin,Freelance adviser
 
Last photo:
Join Date: Jun 2004
Location: San francisco bay area
Age: 55
Posts: 13,129
Wiki Edits: 0

Thanks: 1,299
Thanked 1,139 Times in 1,009 Posts
All I know is you can warp that sheet metal very fast sandblasting. You better really watch yourself.

Brian
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 04-02-2005, 08:17 PM
Bee4Me's Avatar
Problem Child,Hard Case
 

Last journal entry: Strangest job I've ever done
Last photo:
Join Date: Jan 2005
Location: ARK.
Age: 57
Posts: 1,773
Wiki Edits: 0

Thanks: 0
Thanked 1 Time in 1 Post
If your using the 40# one from Harbor,Do yourself a favor and go pick up the gray inline gun for it.It's in the air fitting's & regulator area in a blister pack with a yellow back card. It's ALOT more easy to use and control.Their site search is sucking or I'd get the page for ya.
I have some old plexi glass that I use to cut extra shields out of as they will get eaten up regular,I hope your using a good respirator as well.Any blasting is hazardous to your health and we'd just as soon see you back here.
I spread out a bunch of plastic and took some window screen and taped over the funnel top for cleaning on reuse.
Not saying you can't warp a panel with one but most of us don't have near the compressor to put out that kinda CFM & PSI. Just don't stay in one spot too long,keep it moving and you'll be fine.

You want that metal free of rust,ANY rust.Period.
Thats why your doing this in the first place,Right?
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 04-02-2005, 08:44 PM
Member
 
Last photo:
Join Date: Jan 2005
Location:
Posts: 3,707
Wiki Edits: 0

Thanks: 0
Thanked 2 Times in 2 Posts
You'll be good to go for the interior IMO. Put 2-3 good coats of epoxy on and it'll hold up just fine.
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 04-02-2005, 09:10 PM
S10xGN's Avatar
Gotta love a turbo!
 

Last journal entry: Body on Frame today.
Last photo:
Join Date: Aug 2004
Location: Port Neches, TX
Age: 61
Posts: 1,656
Wiki Edits: 0

Thanks: 0
Thanked 60 Times in 56 Posts
I've heard about warping panels, I've always ASSumed it's heat that does it. Just for a "test" I blasted in one area for a few minutes and reached around behind to feel the backside where I had blasted. It was stone cold - colder than the surrounding metal. Maybe my rig isn't setup right, or maybe the airflow is supercooling the metal. I don't know, maybe it's not heat but some other entity that causes warping. Hèll, maybe I'M warped!

I'll need to get a better hood and more nozzles anyways, so a trip to HF Monday for sure. My rig is the next step up from the 40# unit, not sure which model, but I'll also look for the "gun". Does that one have the "deadman" trigger?
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 04-02-2005, 09:28 PM
Bee4Me's Avatar
Problem Child,Hard Case
 

Last journal entry: Strangest job I've ever done
Last photo:
Join Date: Jan 2005
Location: ARK.
Age: 57
Posts: 1,773
Wiki Edits: 0

Thanks: 0
Thanked 1 Time in 1 Post
No, It has a squeeze handle with a lock ring. It pinch's off the tube the material goes thru for shut off. And, Yeah it will wear out soon enough but at least it's light and you can lock it ON instead of squeezing your hand dead.
I throttle the bottom tank lever to like 1/8-1/4 open depending on media.
The first time is usually a big learning curve (mess)
I actually fitted one of those big blue separators to the inlet,keeps the water done some better than the one it comes with.
It's the heat alright. You ever watch the pro's do some with a biga** LeRoy diesel pounding away at 175 PSI It's not hard to imagine building some heat.
Reply With Quote Quick reply to this message
  #7 (permalink)  
Old 04-02-2005, 10:20 PM
MARTINSR's Avatar
Brian Martin,Freelance adviser
 
Last photo:
Join Date: Jun 2004
Location: San francisco bay area
Age: 55
Posts: 13,129
Wiki Edits: 0

Thanks: 1,299
Thanked 1,139 Times in 1,009 Posts
Heat has nothing to do with it, and YES, a little compressor can warp panels. The condition is "compressive mechanism - localized molecular packing". Each grain of sand acts like a little hammer putting microscopic dents in the metal. These dents are pushing the molecules around. The top layer of the metal gets stretched out warping it up.

I have seen it done many times, by home hobbiest, and pros alike. I could fill this post with all the urls to posts and threads that are on the net discussing sand blasted damage.

http://www.google.com/search?hl=en&i...=Google+Search




Brian
Reply With Quote Quick reply to this message
  #8 (permalink)  
Old 04-02-2005, 11:16 PM
rlackey's Avatar
Rich Lackey
 

Last journal entry: Rich Lackey is back on Hotrodders!
Last photo:
Join Date: Jan 2005
Location: Centurion, South Africa
Age: 34
Posts: 331
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Brian,

It's funny that this has come up again. I remember when I first posted on this forum (probably was my first post) and I was thinking about having my whole bodyshell sandblasted. You and a few others talked me out of it pretty quick, and now I'm doing it all by hand with sandpaper and naval jelly.

I have to say that I'm pretty pleased with the results so far and even though I would have sworn the rust was so bad I had to blast it, some elbow grease and phosphoric acid can work wonders.

But I have also been seeing a lot of pictures of very nice looking sandblasted cars, perfectly clean inside and out top to bottom, probably done in only a few hours. Mine on the other hand is taking me months rather than hours, and I still find myself wondering whether I made the right choice.

In the end I know for certain I won't have any warped panels, but I do wonder all the time what would have happened if I'd just sent the whole thing to the blaster. I also have no idea how I'm going to get the underside of my car as spotless by hand as it would be if it had been blasted.

It seems at least that with some care it is entirely possible to blast a car clean without any damage. My curiosity is killing me, I am tempted just to send in my trunk lid, hood or fenders and see what happens, but I can't do it just because I can't afford to lose any of those items.

Hmm, maybe it's one of those things that will be argued to the death for as long as cars are being restored.

Rich
Reply With Quote Quick reply to this message
  #9 (permalink)  
Old 04-02-2005, 11:50 PM
MARTINSR's Avatar
Brian Martin,Freelance adviser
 
Last photo:
Join Date: Jun 2004
Location: San francisco bay area
Age: 55
Posts: 13,129
Wiki Edits: 0

Thanks: 1,299
Thanked 1,139 Times in 1,009 Posts
The thing is Rich, there is no arguing that it "can" happen. Most will agree with that, where the argument starts is "how" it happens as far as equipment or user. I have to say, I have seen people do it at home with little compressors. I myself had a "Pro" ruin a 1928 Buick door for me.

It is like tossing out that meat that "might" be bad in your fridge. It is expensive, you hate to throw it out. If you eat it and wake up in the middle of the night vomiting, it is too late to start over.

Brian
Reply With Quote Quick reply to this message
  #10 (permalink)  
Old 04-03-2005, 12:04 AM
rlackey's Avatar
Rich Lackey
 

Last journal entry: Rich Lackey is back on Hotrodders!
Last photo:
Join Date: Jan 2005
Location: Centurion, South Africa
Age: 34
Posts: 331
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Yep, I guess it all comes down to what is an acceptable level of risk. For me, even the remote possibility of irrepairable damage is unnacceptable. I do wonder how it can possibly be acceptable for others that actually care about the cars they are building.

It's probably one of those things that "will never happen to me", because you are careful, have done your homework and know what you're doing... until it does happen... probably on that prized project.

I think I just get a bit jealous when I see others with perfect bodyshells that have come from blasting for a few hours, and I've been outside slaving away for weeks, and in the end they will both end up primed and painted and no one will know any better. I start to ask myself why I am doing all this extra work?

But, I guess I can rest assured I won't be waking up vomiting in the middle of the night.

Rich
Reply With Quote Quick reply to this message
  #11 (permalink)  
Old 04-03-2005, 10:01 AM
MARTINSR's Avatar
Brian Martin,Freelance adviser
 
Last photo:
Join Date: Jun 2004
Location: San francisco bay area
Age: 55
Posts: 13,129
Wiki Edits: 0

Thanks: 1,299
Thanked 1,139 Times in 1,009 Posts
LOL
Brian
Reply With Quote Quick reply to this message
  #12 (permalink)  
Old 04-03-2005, 06:09 PM
Bee4Me's Avatar
Problem Child,Hard Case
 

Last journal entry: Strangest job I've ever done
Last photo:
Join Date: Jan 2005
Location: ARK.
Age: 57
Posts: 1,773
Wiki Edits: 0

Thanks: 0
Thanked 1 Time in 1 Post
Whatever the case. I believe it comes down to the "experience" on the end of the hose.
I've blasted many hundred's of parts,panels,ect with all kinds of media and have yet to have a problem.Lucky? No. Just carefull with MY technique.If I even think the meat is bad,it's tossed.I hate being sick.But i'm not scared to attempt something just because.If that was the case,I wouldn't be here in the first place.
Tim had the 59 P/U cab,doors,hood,bed done locally and outside of the extra swiss cheese appearing it was a good shoot.The company is well known and does fabulous work.Again,These guy's KNOW what they are doing.
It's a viable alternative to spending hours toiling away to have a project done and being able to get on with it.
As always though,
It's YOUR project,Do it the way YOU want.
Reply With Quote Quick reply to this message
  #13 (permalink)  
Old 04-03-2005, 06:55 PM
Member
 
Last photo:
Join Date: Jan 2005
Location:
Posts: 3,707
Wiki Edits: 0

Thanks: 0
Thanked 2 Times in 2 Posts
I've also done lots of blasting over the years on exterior sheetmetal without any problems. If you keep your distance and hold the blaster at a 45 degree angle all is well. Only when a person tries to rush the job holding the blaster to close and concentrated does the metal warp. There are two blasting facilites near me that also have no problems with warpage. IMO there is no better surface prep for epoxy primer application. Yes it can be done with no damage if you use your head.
Reply With Quote Quick reply to this message
  #14 (permalink)  
Old 04-04-2005, 08:07 AM
AhX AhX is offline
New Member
 
Join Date: Apr 2005
Location: NJ
Posts: 23
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
I intend to use either walnut shell or glass beads to strip the shell of the car. I will most likely use the walnut shell for the panels and the glass for the firewall. I will use regular sand for the floors.
Reply With Quote Quick reply to this message

Recent Body - Exterior posts with photos

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Hot Rod Forum : Hotrodders Bulletin Board forums, you must first register.
Please enter your desired user name (usually not your first and last name), your email address and other required details in the form below.
User Name:
If you do not want to register, fill this field only and the name will be used as user name for your post.
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Rust Question BT74 Body - Exterior 1 09-28-2004 03:57 PM
Rust prevention question 92redgt Body - Exterior 3 03-14-2004 05:33 PM
phosphoric acid rust converter question zachscc Body - Exterior 1 11-10-2003 04:55 AM
Hotrodders Guidelines -- READ ME Jon Engine 0 06-14-2003 04:53 PM


All times are GMT -6. The time now is 05:43 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.