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SEM Clear Chip Guard - Spray - How does it work?


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Hello, I'm looking for advice on an SEM product: Clear Chip Guard - Aerosol 39804 . I'm getting my 240z ready for summer driving and this year my goal is to try something that prevents all the stone chips along the running boards and rear fender from dinging up the paint. I must spend at least an 1hr per month touching up stone chips. With my tires on 7.5" wide rims and driving on clean highway and smooth roads, I still pick up quite a few small stone dings in the paint - in some cases down thru the primer to the metal.


1) Has anyone tried using the SEM Clear Chip Guard Aerosol - 39804?

SEM Tech. Data Sheet: http://semproducts.com/images/tech_files/CG%20TDS.pdf

2) Does anyone know a better product or technique for adding a clear protective stone chip coating? While also looking very good ...

For a 240z, there are several options for coating the running boards and rear fender under the bumper such that the "Line" or "Boarder" is not very noticeable. In fact if I follow the "Crease" from the Front Fender-to Door-to Rear Fender line - it would not be noticeable as long as the Clear Chip Guard coating is smooth. (See the photos - the crease is about 8 inchs up the bottom of the running board).

Anyway - I'm looking for advice before I get into something I'll regret much more than living with the hours of stone chip touch-up I have today.

Many thanks...



Edited by moritz55
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I'm in the same boat. Fresh paint, hate the look of mud flaps, didn't put "gravel guard" under the paint, don't care for the look either, now what?

I'm thinking 3m clear film. Easy to replace. Thoughts?


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3M clear stone guard film is a good bet . We use the stuff regularly at the shop. Works very well . Its pricey and a little tricky to install especially over large countoured areas. Removing large areas of the product is a pain in the ***, if you screw up or have to remove to paint. When done correctly you almost cant tell its on the car. The other option is a product like 3M #8949 chip coating which must be applied before painting. This product is good for the lower front valances and end caps . The clear SEM is very thin and takes many coats to build up a layer of protection.

Edited by palosfv3
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I like Jim's idea of the clear film. My only concern would be how aggressive the adhesive is on the film. If it ever needed replacing, I would hate to think I might lift any paint, unless there is a product to help release the adhesive other than heat.

The Sem Chip Guard is a neat idea, except it complicates any future repair or repaint needs, and I like simple. The film should be easy to get and looks professional, as many new car manufacturers use a similar product in chip prone areas.


Edited by AZ-240z
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Since the 3m film is expensive, and the SEM needs several coats, and the "gravel guard" needs to be applied before painting, or as one of the last coats, and AZ-240Z was looking for something simple....

The contoured splash guards are NOT like your typical piece of sheet metal splash guard.



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Well, looks like the best bet is the 3M Clear Film based on Palosfv3. Even though the SEM Chip Guard can be easily applied. So ....

==> It sounds like 3M Film (tricky and very, very permanent and tough to remove) is the best bet. It's used on new cars today - clear and almost not noticeable but really should be applied by experts. It's also expensive, not to mention labor costs.

==> SEM Chip Guard is easily applied. Very flexible in use for small or large surfaces. The instructions say 3 wet medium-coats with 5-10mins between. The end result may not be robust/thick enough for the long term. Surface may not be as smooth as desired.

I think I'll expertiment with the SEM Chip Guard on the inside wheel well fender lips. They get chipped up pretty bad and if the material doesn't go on as "Clear & Smooth" as desired.. It's not terrible. I can pick up a 16oz can for $19.00 locally. Anyway I won't be risking the side running board area and lower rear fenders.

I'll take some before and after photos to document my approach and share it here.

In the mean time - maybe we'll get some info with photos of the finished product on cars from fellow Zcar owners that have used SEM Chip Guard a while ago so they can comment on the effectiveness on reducing chips.

Stay tuned ....

Edited by moritz55
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Check with a local dealer to find out who installs the 3M tape locally. I would guess that it would cost around $250.00 to do a 240/260/280. This would be the front fenders rear of the w/o from the lower body line down, the quarters rear of the w/o to the rear body panel from the bottom edge of the bumper down and dont forget a piece for the upper leading edge of the quarter w/o. I have pics of the material installed on a Z but the pics just dont show the tape edges very well.

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Thanks .. I think you convinced me 3M Tape Chip Protection is the best approach for both function and transparent visibility since it's virtually unoticeable. I'll shop around and try to find an expert installer locally near Newburgh or Beacon New York.

Do you happen to know if there is a "Kit" with precut pieces for installing or is this a custom job?

Many thanks...

Edited by moritz55
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I agree with one of the posts above, that a film with a less aggressive adhesive would be better and must be available (you see things packaged with such film all the time). I'll check with a friend that has a Ferrari.

Even if it is not invisible, who cares, as long as it is easily removed?

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Hello, since I purchased a can of SEM Chip Guard -39804, I tried it on the wheel well inside edges. They get chipped up pretty bad and I'm always touching them up so I figured I had nothing to loose tyring it out.

So .. my process steps were for the most part just as described on the spec sheet. SEM Tech. Data Sheet: http://semproducts.com/images/tech_files/CG%20TDS.pdf


1) Cleaned surface from dirt and road film with dish wash detergent, water & spong. Rinse clean and thoroughly dry.

2) Using Scotch-Brite Pad (Gray color ones), rather than 400 grit Sand Paper, I dulled the surfaces enough to prep for base Coat Paint.

3) Then I sprayed 2 light coats of my "Green" Body Base Coat paint. I allowed 10mins between coats and then 20mins for it to dry.

4) Most important part when using the SEM Chip Guard - for maximum gloss and clear/smooth finish:

......... a) Hold can ~20 inches away. Calibrate your spray distance with a tape measure just to be sure you are far enough. Too close leaves a lumpy surface.

......... B) Start by spraying the SEM Chip Guard OFF the surface on paper masking area until the flow is steady/uniform keeping ~20 inches distance from the surface. I applied two passes so it was uniform and had a wet look.

......... c) Wait about ~5 mins, then repeated above applying two passes for another wet coat. Then repeated after another 5mins and did a 3rd application.

5) Drys to touch in 30mins - pretty quick. Pulled tape off immediately and no pulling or sticking to the tape edges.

Photos could have been better, anyway they are ... 000/001 - before, 002/003 - scotch-brite scuffed, 004/005 - green base coat applied, 006/007 - After SEM Chip Guard applied.

Overall .. it' looks pretty good. The SEM coating is defnitely heavy. We'll see how it holds up...









Edited by moritz55
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