Is fiberglass filler profitable to sell on Amazon United States?

The niche generates $277K/yr across 15 tracked products. 90-day search growth is +30.6%. Flapen's verdict: Worth a look (56/100).

How competitive is the fiberglass filler niche?

10 brands and 86 sellers compete. The top 5 products take 68% of clicks and top 5 brands hold 82% of demand.

What do buyers complain about in fiberglass filler?

Top complaints mined from reviews: Flexibility, Advertised Vs Actual Product, Hard Feel. The return rate is 0.3%.

When does demand for fiberglass filler peak?

Demand peaks in May; the busiest month runs 1.8× the quietest.

What does it cost to enter the fiberglass filler niche?

Listings span $7.31–$60.46; the average listing price is $33.19 (sweet spot $15–$100). The average incumbent carries 763 reviews — the moat a new listing must climb.

fiberglass filler

Worth a look

Shows low returns (0.3%), but a failed launch gate (market size, growth, or returns) keeps it on the watch list.

Returns

Incredible0.3%

return rate — above 5% kills the launch gate

Avg price

Incredible$33.19

avg listing price — sweet spot $15–$100

Price range

Great$7.31–$60.46

cheapest to priciest tracked listing — scored on the share inside $15–$100

Review moat

Good762.8

avg incumbent reviews — the moat a new listing must climb

Conversion

Good5.8%

search→purchase rate — share of searches ending in a sale

Growth

Good+30.6%

90-day search growth — must beat 0% to launch

Market size

Good$277K

$277K/yr · 143K searches

Brand share

Okay82%

top-5 brand share — brands hold most of the demand

Quality gap

Okay4.6★

avg incumbent rating — lower means beatable quality

Competition

Okay68%

top-5 click share — leaders hold, buyers still browse

According to Flapen's Amazon United States niche tracking, fiberglass filler is a $277K/yr Amazon United States market (143K searches/yr). The top 5 brands hold 82% of demand. Demand peaks in May. Verdict: Worth a look — 56/100.

Data updated Jul 8, 2026 · scored weekly · How we score niches

fiberglass filler market data

Units sold / yr: 10K–13K; avg 750–1,000/product
Revenue / yr: $332K–$415K; units × avg price
Conversion rate: 5.8%
Avg BSR: #47
Page quality: 0%
Prime: 80%
Sponsored: 87%
Out of stock: 0.0%
Avg brand age: 67 months
Avg seller age: 172 days

Competition & brand share

The top 5 products take 68% of clicks — established leaders, but buyers still shop beyond them.

Brands

10 rising

Sellers

Top-5 brand share

82%

Top 20: 100%

Top-5 click share

68%

Top 20: 100%

Open market

13%

bondo28%
3M19%
J-B Weld14%
U.S. Chemical & Plastics12%
Evercoat9%
TotalBoat5%
Open — no brand owns it (4 brands, 13%)

Demand & seasonality

Weekly Amazon search volume, last 104 weeks — +30.6% search growth over the last 90 days.

Peak months: May · busiest ÷ quietest = 1.8×

Open Trend

Top fiberglass filler search terms

fiberglass filler27K/yr +32.6%4.3% conv.
fiberglass body filler16K/yr +14.9%5.7% conv.
bondo glass12K/yr +30.4%6.6% conv.
fiberglass bondo12K/yr +53.2%7.4% conv.
duraglass body filler8K/yr +6.4%6.5% conv.
short strand fiberglass filler6K/yr +68.8%6.8% conv.
duraglass9K/yr -3.8%3.6% conv.
bondo fiberglass6K/yr +63.1%6.2% conv.
kitty hair fiberglass filler6K/yr +18.0%5.8% conv.
fiberglass putty5K/yr +51.3%2.2% conv.

All search terms

Top fiberglass filler products on Amazon

Each bubble is one product — market share against review moat; bubble size tracks estimated sales, color grades how beatable the incumbent looks.

Beatable (≤4.3★) Contested Strong incumbent (>4.7★)

All 15 tracked products in this niche — three views at once, no toggling.

Top sellers

by 90-day click share

3M Bondo Short Strand Fiberglass Reinforced Filler 1.37 LB (621 g) with Bondo Cream Hardener 0.5 oz (14g) Repair Holes Up To 0.5 IN Waterproof (SS-PT-ES)

bondo$15.034.6★1,659 rev

J-B Weld Quart - Fiberglass Short-Strained Filler

J-B Weld$23.944.7★267 rev

Bondo Bondo-Hair Long Strand Fiberglass Reinforced Filler 00762 1 Quart

3M$16.254.6★1,147 rev

Bondo Glass Short Strand Reinforced Fiberglass Filler Stage 2 2.56 Oz Filler and 1 Oz Cream Hardener

3M$21.254.7★2,330 rev

Duraglas Fiberglass Filled Filler 1 Gallon

U.S. Chemical & Plastics$60.464.7★813 rev

Newest

by launch date

Evercoat Body Shop 105010 Pro-Grade Reinforced Filler Added Strength and Durability for Dents in Aluminum Fiberglass & More Easy Mix Hardener Included 13 Fl Oz.

EVERCOAT Body Shop$16.8451 rev

1y ago

J-B Weld Quart - Fiberglass Short-Strained Filler

J-B Weld$23.94267 rev

1y ago

LAUCO Ultra Fiber Sandable Fiberglass Filler Bridges Holes Water Resistant Lightweight for Fiberglass Steel Plastics Base Color of Yellow-Green 3 Liters

LAUCO$53.28100 rev

2y ago

Frienda 6 Pcs Body Filler Spreaders Plastic Tools for Automotive Applying Putties Glazes Caulks and Paint (3 Sizes)

Frienda$7.311,507 rev

3y ago

TotalBoat Polyester Structural Repair Putty - Marine Grade Long Strand Fiber Fiberglass Reinforced Filler for Boat and Automotive Repair (Quart Kit)

TotalBoat$40.23869 rev

8y ago

What buyers say about fiberglass filler

What buyers praise and complain about, mined from review topics.

What buyers love

Quality-Overall26%

“Great product as”

Efficiency13%

“Worked good for what I needed”

Ease Of Use11%

“This product is easy to use”

Value For Money11%

“great price”

Maintenance And Repair9%

“Good small kit for small repairs”

Advertised Vs Actual Product6%

“workes as advertised”

Durability4%

“Worked great and lasting not falling apart”

Water Resistance3%

“This is a good quality waterproof body filler with long strands of fiberglass strands to make it much stronger”

Assembly/Installation2%

“it will set up on you in just minutes”

Ease Of Cleaning2%

“didn't make to much of a mess”

What buyers complain about

Flexibility15%

“Unfortunately, the one I received is hard as a rock with almost no flex at all”

Advertised Vs Actual Product15%

“Deceptive Ad & Non Returnable”

Hard Feel12%

“Hard as a rock”

Strength8%

“Very brittle”

Quality-Overall5%

“Complete Garbage”

Instructions/User Manual/Troubleshooting4%

“After reading detailed instructions determined wouldnt work for my project”

Color4%

“You'd think they would provide a off-color hardener”

Texture/Consistency-Overall4%

“the second batch I used today does not have the same smooth consistency as the first”

Leak-Proof4%

“Leaking”

Durability4%

“Wouldnt fully cure after 4 days”

Top return reasons

Flexibility16%

Size-Overall15%

Material Quality12%

Functionality-Overall11%

Defective Material/Parts9%

Value For Money7%