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[ShaneDiego]

Hello everyone, new to the forum here. I’ve searched high and low but can’t find any info on this specific topic. Hoping some of you might be able to lend some help...

I’m doing custom leather upholstery on a set of Sparco Evo L’s. I patterned all the parts and first sewed a test cover in a vinyl with very similar stretch and overall characteristics to the real leather. The cover was super loose in some areas, particularly the concave curves leading down from the shoulder bolsters and the transition from back to seat area. I ended up darting (clipping) the test cover right in those areas and marking the slack. Which I then transferred to my pattern and made the adjustments. The second test cover came out nearly spot on. All nice and tight throughout the curves and twists of the seat.

My question is, does anyone have experience with these types of complex curves and how they pattern them correctly from the start? I used the same vinyl as the test cover to pattern and they were true to my lines but once made and installed it was over a half inch baggy on both sides of the bolster and skirt. I could not have even stretched or predicted it to be that lose off of my original patterns had I not seen the test cover and seen the result. I do a lot of marine upholstery where everything we do is 3/8” or even 1/4” seam allowance and sewn to a half inch to allow for stretch and a tight fitting cover. But even that would not have gathered the slack I had in the first cover. From what I’ve gathered, this technique isn’t really used in auto upholstery and most of the time, seam allowance is sewn to its true spec (I.e. 1/2” SA is sewn to a 1/2”) long winded explanation short, how do you guys pattern complex twists and curves (mainly concave curves) correctly from the start so that the cover fits nice and tight without wrinkles and extra material. I even tried light weight clear vinyl which I use more often than not, but it wouldn’t pin flat and tight to these curves that are so complex. Hope this makes some sort of sense and any help is most greatly appreciated

Stitch on!
-Shane Diego

[BigRig]

Material stretches over time and that is often not seen or accounted for in the template making from your old cover. Most likely though you are working with old foam that has lost its full shape. I would consider looking for new foam and fit the cover you made to see what the result is before you start messing with it any further. If the were not darts sewn into the original cover then they do not need to be there.

[ShaneDiego]

Thanks BigRig for your reply,

The seat is brand new so foam is true as it comes from the factory. Granted Sparco’s foam job leaves A LOT to be desired... it’s super thin and cheap... by darted, I meant that I pinched in the slack at the seams on the test cover and clipped it so I could Mark it to it’s true size to make adjustments. I didn’t add any literal darts. But they use a cheap fabric in their stock seats that is easy to stretch and manipulate. I patterned to even lines on the foam with no real wrinkles in my patterns. What is perplexing to me is the fact that the concave areas ended up being so loose from what I patterned to initially which was tight and seemed to be right on the money. Just seeing if there’s any tricks to accounting for those complex areas... I feel like a good pattern to my lines should yield a close result but it was so far off that I have no real clue as to how I could have patterned better in the future to account for the bagginess I found in those areas... from all the research I’ve done, there isn’t much info on these types of race seat upholstery. I now have a solid pattern for this seat after two test covers but I feel like there has to be a better way of getting the pattern closer on the first try and from what I’ve seen/tried, I’m kinda stumped...

[BigRig]

@ShaneDiego , you have to rule out adhesives to hold those pieces down. Make sure those seam lines match up with the original seam lines off a bit and it just plain not fitting. Can you take a picture of the bottom of the seat to show us how it is attached.

[John]

Racing seats are difficultI I pattern all my seats using clear vinyl. On racing seats you usually dont use any foam backing. This is probably why your covers are so loose. I suggest making your patterns and adding 1/8" seam allowance and sewing at 1/2" or "3/8 seam allowance. also consider using 1/4" foam backing.

I hope this helps.